qemu-storage-daemon-qmp-ref - Man Page

Members

• id (string) -- unique snapshot id
• name (string) -- user chosen name
• vm-state-size (int) -- size of the VM state
• date-sec (int) -- UTC date of the snapshot in seconds
• date-nsec (int) -- fractional part in nano seconds to be used with date-sec
• vm-clock-sec (int) -- VM clock relative to boot in seconds
• vm-clock-nsec (int) -- fractional part in nano seconds to be used with vm-clock-sec
• icount (int, optional) -- Current instruction count.  Appears when execution record/replay is enabled.  Used for "time-traveling" to match the moment in the recorded execution with the snapshots.  This counter may be obtained through query-replay command (since 5.2)

Members

• format (BlockdevQcow2EncryptionFormat) -- The encryption format

Members

• The members of ImageInfoSpecificQCow2EncryptionBase.
• When format is luks: The members of QCryptoBlockInfoLUKS.

Members

• compat (string) -- compatibility level
• data-file (string, optional) -- the filename of the external data file that is stored in the image and used as a default for opening the image (since: 4.0)
• data-file-raw (boolean, optional) -- True if the external data file must stay valid as a standalone (read-only) raw image without looking at qcow2 metadata (since: 4.0)
• extended-l2 (boolean, optional) -- true if the image has extended L2 entries; only valid for compat >= 1.1 (since 5.2)
• lazy-refcounts (boolean, optional) -- on or off; only valid for compat >= 1.1
• corrupt (boolean, optional) -- true if the image has been marked corrupt; only valid for compat >= 1.1 (since 2.2)
• refcount-bits (int) -- width of a refcount entry in bits (since 2.3)
• encrypt (ImageInfoSpecificQCow2Encryption, optional) -- details about encryption parameters; only set if image is encrypted (since 2.10)
• bitmaps ([Qcow2BitmapInfo], optional) -- A list of qcow2 bitmap details (since 4.0)
• compression-type (Qcow2CompressionType) -- the image cluster compression method (since 5.1)

Members

• create-type (string) -- The create type of VMDK image
• cid (int) -- Content id of image
• parent-cid (int) -- Parent VMDK image's cid
• extents ([VmdkExtentInfo]) -- List of extent files

Information about a VMDK extent file

Members

• filename (string) -- Name of the extent file
• format (string) -- Extent type (e.g. FLAT or SPARSE)
• virtual-size (int) -- Number of bytes covered by this extent
• cluster-size (int, optional) -- Cluster size in bytes (for non-flat extents)
• compressed (boolean, optional) -- Whether this extent contains compressed data

Members

• encryption-format (RbdImageEncryptionFormat, optional) -- Image encryption format

Members

• extent-size-hint (int, optional) -- Extent size hint (if available)

Values

• luks -- Since 2.7
• rbd -- Since 6.1
• file -- Since 8.0
• qcow2 -- Not documented
• vmdk -- Not documented

Members

• data (ImageInfoSpecificQCow2) -- image information specific to QCOW2

Members

• data (ImageInfoSpecificVmdk) -- image information specific to VMDK

Members

• data (QCryptoBlockInfoLUKS) -- image information specific to LUKS

Members

• data (ImageInfoSpecificRbd) -- image information specific to RBD

Members

• data (ImageInfoSpecificFile) -- image information specific to files

A discriminated record of image format specific information structures.

Members

• type (ImageInfoSpecificKind) -- block driver name
• When type is qcow2: The members of ImageInfoSpecificQCow2Wrapper.
• When type is vmdk: The members of ImageInfoSpecificVmdkWrapper.
• When type is luks: The members of ImageInfoSpecificLUKSWrapper.
• When type is rbd: The members of ImageInfoSpecificRbdWrapper.
• When type is file: The members of ImageInfoSpecificFileWrapper.

Information about a QEMU image file

Members

• filename (string) -- name of the image file
• format (string) -- format of the image file
• virtual-size (int) -- maximum capacity in bytes of the image
• actual-size (int, optional) -- actual size on disk in bytes of the image
• dirty-flag (boolean, optional) -- true if image is not cleanly closed
• cluster-size (int, optional) -- size of a cluster in bytes
• encrypted (boolean, optional) -- true if the image is encrypted
• compressed (boolean, optional) -- true if the image is compressed (Since 1.7)
• backing-filename (string, optional) -- name of the backing file
• full-backing-filename (string, optional) -- full path of the backing file
• backing-filename-format (string, optional) -- the format of the backing file
• snapshots ([SnapshotInfo], optional) -- list of VM snapshots
• format-specific (ImageInfoSpecific, optional) -- structure supplying additional format-specific information (since 1.7)

Information about a QEMU image file, and potentially its backing image

Members

• backing-image (ImageInfo, optional) -- info of the backing image
• The members of BlockNodeInfo.

Information about all nodes in the block graph starting at some node, annotated with information about that node in relation to its parent.

Members

• name (string) -- Child name of the root node in the BlockGraphInfo struct, in its role as the child of some undescribed parent node
• info (BlockGraphInfo) -- Block graph information starting at this node

Information about all nodes in a block (sub)graph in the form of BlockNodeInfo data.  The base BlockNodeInfo struct contains the information for the (sub)graph's root node.

Members

• children ([BlockChildInfo]) -- Array of links to this node's child nodes' information
• The members of BlockNodeInfo.

Information about a QEMU image file check

Members

• filename (string) -- name of the image file checked
• format (string) -- format of the image file checked
• check-errors (int) -- number of unexpected errors occurred during check
• image-end-offset (int, optional) -- offset (in bytes) where the image ends, this field is present if the driver for the image format supports it
• corruptions (int, optional) -- number of corruptions found during the check if any
• leaks (int, optional) -- number of leaks found during the check if any
• corruptions-fixed (int, optional) -- number of corruptions fixed during the check if any
• leaks-fixed (int, optional) -- number of leaks fixed during the check if any
• total-clusters (int, optional) -- total number of clusters, this field is present if the driver for the image format supports it
• allocated-clusters (int, optional) -- total number of allocated clusters, this field is present if the driver for the image format supports it
• fragmented-clusters (int, optional) -- total number of fragmented clusters, this field is present if the driver for the image format supports it
• compressed-clusters (int, optional) -- total number of compressed clusters, this field is present if the driver for the image format supports it

Mapping information from a virtual block range to a host file range

Members

• start (int) -- virtual (guest) offset of the first byte described by this entry
• length (int) -- the number of bytes of the mapped virtual range
• data (boolean) -- reading the image will actually read data from a file (in particular, if offset is present this means that the sectors are not simply preallocated, but contain actual data in raw format)
• zero (boolean) -- whether the virtual blocks read as zeroes
• compressed (boolean) -- true if the data is stored compressed (since 8.2)
• depth (int) -- number of layers (0 = top image, 1 = top image's backing file, ..., n - 1 = bottom image (where n is the number of images in the chain)) before reaching one for which the range is allocated
• present (boolean) -- true if this layer provides the data, false if adding a backing layer could impact this region (since 6.1)
• offset (int, optional) -- if present, the image file stores the data for this range in raw format at the given (host) offset
• filename (string, optional) -- filename that is referred to by offset

Cache mode information for a block device

Members

• writeback (boolean) -- true if writeback mode is enabled
• direct (boolean) -- true if the host page cache is bypassed (O_DIRECT)
• no-flush (boolean) -- true if flush requests are ignored for the device

Information about the backing device for a block device.

Members

• file (string) -- the filename of the backing device
• node-name (string, optional) -- the name of the block driver node (Since 2.0)
• ro (boolean) -- true if the backing device was open read-only
• drv (string) -- the name of the block format used to open the backing device. As of 0.14 this can be: 'blkdebug', 'bochs', 'cloop', 'cow', 'dmg', 'file', 'file', 'ftp', 'ftps', 'host_cdrom', 'host_device', 'http', 'https', 'luks', 'nbd', 'parallels', 'qcow', 'qcow2', 'raw', 'vdi', 'vmdk', 'vpc', 'vvfat' 2.2: 'archipelago' added, 'cow' dropped 2.3: 'host_floppy' deprecated 2.5: 'host_floppy' dropped 2.6: 'luks' added 2.8: 'replication' added, 'tftp' dropped 2.9: 'archipelago' dropped
• backing_file (string, optional) -- the name of the backing file (for copy-on-write)
• backing_file_depth (int) -- number of files in the backing file chain (since: 1.2)
• active (boolean) -- true if the backend is active; typical cases for inactive backends are on the migration source instance after migration completes and on the destination before it completes. (since: 10.0)
• encrypted (boolean) -- true if the backing device is encrypted
• detect_zeroes (BlockdevDetectZeroesOptions) -- detect and optimize zero writes (Since 2.1)
• bps (int) -- total throughput limit in bytes per second is specified
• bps_rd (int) -- read throughput limit in bytes per second is specified
• bps_wr (int) -- write throughput limit in bytes per second is specified
• iops (int) -- total I/O operations per second is specified
• iops_rd (int) -- read I/O operations per second is specified
• iops_wr (int) -- write I/O operations per second is specified
• image (ImageInfo) -- the info of image used (since: 1.6)
• bps_max (int, optional) -- total throughput limit during bursts, in bytes (Since 1.7)
• bps_rd_max (int, optional) -- read throughput limit during bursts, in bytes (Since 1.7)
• bps_wr_max (int, optional) -- write throughput limit during bursts, in bytes (Since 1.7)
• iops_max (int, optional) -- total I/O operations per second during bursts, in bytes (Since 1.7)
• iops_rd_max (int, optional) -- read I/O operations per second during bursts, in bytes (Since 1.7)
• iops_wr_max (int, optional) -- write I/O operations per second during bursts, in bytes (Since 1.7)
• bps_max_length (int, optional) -- maximum length of the bps_max burst period, in seconds.  (Since 2.6)
• bps_rd_max_length (int, optional) -- maximum length of the bps_rd_max burst period, in seconds.  (Since 2.6)
• bps_wr_max_length (int, optional) -- maximum length of the bps_wr_max burst period, in seconds.  (Since 2.6)
• iops_max_length (int, optional) -- maximum length of the iops burst period, in seconds.  (Since 2.6)
• iops_rd_max_length (int, optional) -- maximum length of the iops_rd_max burst period, in seconds.  (Since 2.6)
• iops_wr_max_length (int, optional) -- maximum length of the iops_wr_max burst period, in seconds.  (Since 2.6)
• iops_size (int, optional) -- an I/O size in bytes (Since 1.7)
• group (string, optional) -- throttle group name (Since 2.4)
• cache (BlockdevCacheInfo) -- the cache mode used for the block device (since: 2.3)
• write_threshold (int) -- configured write threshold for the device.  0 if disabled.  (Since 2.3)
• dirty-bitmaps ([BlockDirtyInfo], optional) -- dirty bitmaps information (only present if node has one or more dirty bitmaps) (Since 4.2)

An enumeration of block device I/O status.

Values

• ok -- The last I/O operation has succeeded
• failed -- The last I/O operation has failed
• nospace -- The last I/O operation has failed due to a no-space condition

Block dirty bitmap information.

Members

• name (string, optional) -- the name of the dirty bitmap (Since 2.4)
• count (int) -- number of dirty bytes according to the dirty bitmap
• granularity (int) -- granularity of the dirty bitmap in bytes (since 1.4)
• recording (boolean) -- true if the bitmap is recording new writes from the guest.  (since 4.0)
• busy (boolean) -- true if the bitmap is in-use by some operation (NBD or jobs) and cannot be modified via QMP or used by another operation. (since 4.0)
• persistent (boolean) -- true if the bitmap was stored on disk, is scheduled to be stored on disk, or both.  (since 4.0)
• inconsistent (boolean, optional) -- true if this is a persistent bitmap that was improperly stored.  Implies persistent to be true; recording and busy to be false.  This bitmap cannot be used.  To remove it, use block-dirty-bitmap-remove.  (Since 4.0)

An enumeration of flags that a bitmap can report to the user.

Values

• in-use -- This flag is set by any process actively modifying the qcow2 file, and cleared when the updated bitmap is flushed to the qcow2 image.  The presence of this flag in an offline image means that the bitmap was not saved correctly after its last usage, and may contain inconsistent data.
• auto -- The bitmap must reflect all changes of the virtual disk by any application that would write to this qcow2 file.

Qcow2 bitmap information.

Members

• name (string) -- the name of the bitmap
• granularity (int) -- granularity of the bitmap in bytes
• flags ([Qcow2BitmapInfoFlags]) -- flags of the bitmap

Block latency histogram.

Members

• boundaries ([int]) -- list of interval boundary values in nanoseconds, all greater than zero and in ascending order.  For example, the list [10, 50, 100] produces the following histogram intervals: [0, 10), [10, 50), [50, 100), [100, +inf).

• bins ([int]) --

  list of io request counts corresponding to histogram intervals, one more element than boundaries has.  For the example above, bins may be something like [3, 1, 5, 2], and corresponding histogram looks like:

  5|           *
  4|           *
  3| *         *
  2| *         *    *
  1| *    *    *    *
   +------------------
       10   50   100

Block device information.  This structure describes a virtual device and the backing device associated with it.

Members

• device (string) -- The device name associated with the virtual device.
• qdev (string, optional) -- The qdev ID, or if no ID is assigned, the QOM path of the block device.  (since 2.10)
• type (string) -- This field is returned only for compatibility reasons, it should not be used (always returns 'unknown')
• removable (boolean) -- True if the device supports removable media.
• locked (boolean) -- True if the guest has locked this device from having its media removed
• tray_open (boolean, optional) -- True if the device's tray is open (only present if it has a tray)
• io-status (BlockDeviceIoStatus, optional) -- BlockDeviceIoStatus.  Only present if the device supports it and the VM is configured to stop on errors (supported device models: virtio-blk, IDE, SCSI except scsi-generic)
• inserted (BlockDeviceInfo, optional) -- BlockDeviceInfo describing the device if media is present

Image file size calculation information.  This structure describes the size requirements for creating a new image file.

The size requirements depend on the new image file format.  File size always equals virtual disk size for the 'raw' format, even for sparse POSIX files.  Compact formats such as 'qcow2' represent unallocated and zero regions efficiently so file size may be smaller than virtual disk size.

The values are upper bounds that are guaranteed to fit the new image file.  Subsequent modification, such as internal snapshot or further bitmap creation, may require additional space and is not covered here.

Members

• required (int) -- Size required for a new image file, in bytes, when copying just allocated guest-visible contents.
• fully-allocated (int) -- Image file size, in bytes, once data has been written to all sectors, when copying just guest-visible contents.
• bitmaps (int, optional) -- Additional size required if all the top-level bitmap metadata in the source image were to be copied to the destination, present only when source and destination both support persistent bitmaps.  (since 5.1)

Get a list of BlockInfo for all virtual block devices.

Return

[BlockInfo] -- a list of BlockInfo describing each virtual block device. Filter nodes that were created implicitly are skipped over.

Example:

-> { "execute": "query-block" }
<- {
      "return":[
         {
            "io-status": "ok",
            "device":"ide0-hd0",
            "locked":false,
            "removable":false,
            "inserted":{
               "ro":false,
               "drv":"qcow2",
               "encrypted":false,
               "file":"disks/test.qcow2",
               "backing_file_depth":1,
               "bps":1000000,
               "bps_rd":0,
               "bps_wr":0,
               "iops":1000000,
               "iops_rd":0,
               "iops_wr":0,
               "bps_max": 8000000,
               "bps_rd_max": 0,
               "bps_wr_max": 0,
               "iops_max": 0,
               "iops_rd_max": 0,
               "iops_wr_max": 0,
               "iops_size": 0,
               "detect_zeroes": "on",
               "write_threshold": 0,
               "image":{
                  "filename":"disks/test.qcow2",
                  "format":"qcow2",
                  "virtual-size":2048000,
                  "backing_file":"base.qcow2",
                  "full-backing-filename":"disks/base.qcow2",
                  "backing-filename-format":"qcow2",
                  "snapshots":[
                     {
                        "id": "1",
                        "name": "snapshot1",
                        "vm-state-size": 0,
                        "date-sec": 10000200,
                        "date-nsec": 12,
                        "vm-clock-sec": 206,
                        "vm-clock-nsec": 30
                     }
                  ],
                  "backing-image":{
                      "filename":"disks/base.qcow2",
                      "format":"qcow2",
                      "virtual-size":2048000
                  }
               }
            },
            "qdev": "ide_disk",
            "type":"unknown"
         },
         {
            "io-status": "ok",
            "device":"ide1-cd0",
            "locked":false,
            "removable":true,
            "qdev": "/machine/unattached/device[23]",
            "tray_open": false,
            "type":"unknown"
         },
         {
            "device":"floppy0",
            "locked":false,
            "removable":true,
            "qdev": "/machine/unattached/device[20]",
            "type":"unknown"
         },
         {
            "device":"sd0",
            "locked":false,
            "removable":true,
            "type":"unknown"
         }
      ]
   }

Statistics of a block device during a given interval of time.

Members

• interval_length (int) -- Interval used for calculating the statistics, in seconds.
• min_rd_latency_ns (int) -- Minimum latency of read operations in the defined interval, in nanoseconds.
• min_wr_latency_ns (int) -- Minimum latency of write operations in the defined interval, in nanoseconds.
• min_zone_append_latency_ns (int) -- Minimum latency of zone append operations in the defined interval, in nanoseconds (since 8.1)
• min_flush_latency_ns (int) -- Minimum latency of flush operations in the defined interval, in nanoseconds.
• max_rd_latency_ns (int) -- Maximum latency of read operations in the defined interval, in nanoseconds.
• max_wr_latency_ns (int) -- Maximum latency of write operations in the defined interval, in nanoseconds.
• max_zone_append_latency_ns (int) -- Maximum latency of zone append operations in the defined interval, in nanoseconds (since 8.1)
• max_flush_latency_ns (int) -- Maximum latency of flush operations in the defined interval, in nanoseconds.
• avg_rd_latency_ns (int) -- Average latency of read operations in the defined interval, in nanoseconds.
• avg_wr_latency_ns (int) -- Average latency of write operations in the defined interval, in nanoseconds.
• avg_zone_append_latency_ns (int) -- Average latency of zone append operations in the defined interval, in nanoseconds (since 8.1)
• avg_flush_latency_ns (int) -- Average latency of flush operations in the defined interval, in nanoseconds.
• avg_rd_queue_depth (number) -- Average number of pending read operations in the defined interval.
• avg_wr_queue_depth (number) -- Average number of pending write operations in the defined interval.
• avg_zone_append_queue_depth (number) -- Average number of pending zone append operations in the defined interval (since 8.1).

Statistics of a virtual block device or a block backing device.

Members

• rd_bytes (int) -- The number of bytes read by the device.
• wr_bytes (int) -- The number of bytes written by the device.
• zone_append_bytes (int) -- The number of bytes appended by the zoned devices (since 8.1)
• unmap_bytes (int) -- The number of bytes unmapped by the device (Since 4.2)
• rd_operations (int) -- The number of read operations performed by the device.
• wr_operations (int) -- The number of write operations performed by the device.
• zone_append_operations (int) -- The number of zone append operations performed by the zoned devices (since 8.1)
• flush_operations (int) -- The number of cache flush operations performed by the device (since 0.15)
• unmap_operations (int) -- The number of unmap operations performed by the device (Since 4.2)
• rd_total_time_ns (int) -- Total time spent on reads in nanoseconds (since 0.15).
• wr_total_time_ns (int) -- Total time spent on writes in nanoseconds (since 0.15).
• zone_append_total_time_ns (int) -- Total time spent on zone append writes in nanoseconds (since 8.1)
• flush_total_time_ns (int) -- Total time spent on cache flushes in nanoseconds (since 0.15).
• unmap_total_time_ns (int) -- Total time spent on unmap operations in nanoseconds (Since 4.2)
• wr_highest_offset (int) -- The offset after the greatest byte written to the device.  The intended use of this information is for growable sparse files (like qcow2) that are used on top of a physical device.
• rd_merged (int) -- Number of read requests that have been merged into another request (Since 2.3).
• wr_merged (int) -- Number of write requests that have been merged into another request (Since 2.3).
• zone_append_merged (int) -- Number of zone append requests that have been merged into another request (since 8.1)
• unmap_merged (int) -- Number of unmap requests that have been merged into another request (Since 4.2)
• idle_time_ns (int, optional) -- Time since the last I/O operation, in nanoseconds. If the field is absent it means that there haven't been any operations yet (Since 2.5).
• failed_rd_operations (int) -- The number of failed read operations performed by the device (Since 2.5)
• failed_wr_operations (int) -- The number of failed write operations performed by the device (Since 2.5)
• failed_zone_append_operations (int) -- The number of failed zone append write operations performed by the zoned devices (since 8.1)
• failed_flush_operations (int) -- The number of failed flush operations performed by the device (Since 2.5)
• failed_unmap_operations (int) -- The number of failed unmap operations performed by the device (Since 4.2)
• invalid_rd_operations (int) -- The number of invalid read operations performed by the device (Since 2.5)
• invalid_wr_operations (int) -- The number of invalid write operations performed by the device (Since 2.5)
• invalid_zone_append_operations (int) -- The number of invalid zone append operations performed by the zoned device (since 8.1)
• invalid_flush_operations (int) -- The number of invalid flush operations performed by the device (Since 2.5)
• invalid_unmap_operations (int) -- The number of invalid unmap operations performed by the device (Since 4.2)
• account_invalid (boolean) -- Whether invalid operations are included in the last access statistics (Since 2.5)
• account_failed (boolean) -- Whether failed operations are included in the latency and last access statistics (Since 2.5)
• timed_stats ([BlockDeviceTimedStats]) -- Statistics specific to the set of previously defined intervals of time (Since 2.5)
• rd_latency_histogram (BlockLatencyHistogramInfo, optional) -- BlockLatencyHistogramInfo.  (Since 4.0)
• wr_latency_histogram (BlockLatencyHistogramInfo, optional) -- BlockLatencyHistogramInfo.  (Since 4.0)
• zone_append_latency_histogram (BlockLatencyHistogramInfo, optional) -- BlockLatencyHistogramInfo. (since 8.1)
• flush_latency_histogram (BlockLatencyHistogramInfo, optional) -- BlockLatencyHistogramInfo.  (Since 4.0)

File driver statistics

Members

• discard-nb-ok (int) -- The number of successful discard operations performed by the driver.
• discard-nb-failed (int) -- The number of failed discard operations performed by the driver.
• discard-bytes-ok (int) -- The number of bytes discarded by the driver.

NVMe driver statistics

Members

• completion-errors (int) -- The number of completion errors.
• aligned-accesses (int) -- The number of aligned accesses performed by the driver.
• unaligned-accesses (int) -- The number of unaligned accesses performed by the driver.

Block driver specific statistics

Members

• driver (BlockdevDriver) -- block driver name
• When driver is file: The members of BlockStatsSpecificFile.
• When driver is host_device: The members of BlockStatsSpecificFile.
• When driver is nvme: The members of BlockStatsSpecificNvme.

Statistics of a virtual block device or a block backing device.

Members

• device (string, optional) -- If the stats are for a virtual block device, the name corresponding to the virtual block device.
• node-name (string, optional) -- The node name of the device.  (Since 2.3)
• qdev (string, optional) -- The qdev ID, or if no ID is assigned, the QOM path of the block device.  (since 3.0)
• stats (BlockDeviceStats) -- A BlockDeviceStats for the device.
• driver-specific (BlockStatsSpecific, optional) -- Optional driver-specific stats.  (Since 4.2)
• parent (BlockStats, optional) -- This describes the file block device if it has one. Contains recursively the statistics of the underlying protocol (e.g. the host file for a qcow2 image).  If there is no underlying protocol, this field is omitted
• backing (BlockStats, optional) -- This describes the backing block device if it has one. (Since 2.0)

Query the BlockStats for all virtual block devices.

Arguments

• query-nodes (boolean, optional) -- If true, the command will query all the block nodes that have a node name, in a list which will include "parent" information, but not "backing".  If false or omitted, the behavior is as before - query all the device backends, recursively including their "parent" and "backing".  Filter nodes that were created implicitly are skipped over in this mode.  (Since 2.3)

Return

[BlockStats] -- A list of BlockStats for each virtual block devices.

Example:

-> { "execute": "query-blockstats" }
<- {
      "return":[
         {
            "device":"ide0-hd0",
            "parent":{
               "stats":{
                  "wr_highest_offset":3686448128,
                  "wr_bytes":9786368,
                  "wr_operations":751,
                  "rd_bytes":122567168,
                  "rd_operations":36772
                  "wr_total_times_ns":313253456
                  "rd_total_times_ns":3465673657
                  "flush_total_times_ns":49653
                  "flush_operations":61,
                  "rd_merged":0,
                  "wr_merged":0,
                  "idle_time_ns":2953431879,
                  "account_invalid":true,
                  "account_failed":false
               }
            },
            "stats":{
               "wr_highest_offset":2821110784,
               "wr_bytes":9786368,
               "wr_operations":692,
               "rd_bytes":122739200,
               "rd_operations":36604
               "flush_operations":51,
               "wr_total_times_ns":313253456
               "rd_total_times_ns":3465673657
               "flush_total_times_ns":49653,
               "rd_merged":0,
               "wr_merged":0,
               "idle_time_ns":2953431879,
               "account_invalid":true,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[23]"
         },
         {
            "device":"ide1-cd0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[24]"
         },
         {
            "device":"floppy0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            },
            "qdev": "/machine/unattached/device[16]"
         },
         {
            "device":"sd0",
            "stats":{
               "wr_highest_offset":0,
               "wr_bytes":0,
               "wr_operations":0,
               "rd_bytes":0,
               "rd_operations":0
               "flush_operations":0,
               "wr_total_times_ns":0
               "rd_total_times_ns":0
               "flush_total_times_ns":0,
               "rd_merged":0,
               "wr_merged":0,
               "account_invalid":false,
               "account_failed":false
            }
         }
      ]
   }

An enumeration of possible behaviors for errors on I/O operations. The exact meaning depends on whether the I/O was initiated by a guest or by a block job

Values

• report -- for guest operations, report the error to the guest; for jobs, cancel the job
• ignore -- ignore the error, only report a QMP event (BLOCK_IO_ERROR or BLOCK_JOB_ERROR).  The backup, mirror and commit block jobs retry the failing request later and may still complete successfully.  The stream block job continues to stream and will complete with an error.
• enospc -- same as stop on ENOSPC, same as report otherwise.
• stop -- for guest operations, stop the virtual machine; for jobs, pause the job
• auto -- inherit the error handling policy of the backend (since: 2.7)

An enumeration of possible behaviors for the initial synchronization phase of storage mirroring.

Values

• top -- copies data in the topmost image to the destination
• full -- copies data from all images to the destination
• none -- only copy data written from now on
• incremental -- only copy data described by the dirty bitmap. (since: 2.4)
• bitmap -- only copy data described by the dirty bitmap.  (since: 4.2) Behavior on completion is determined by the BitmapSyncMode.

An enumeration of possible behaviors for the synchronization of a bitmap when used for data copy operations.

Values

• on-success -- The bitmap is only synced when the operation is successful.  This is the behavior always used for 'INCREMENTAL' backups.
• never -- The bitmap is never synchronized with the operation, and is treated solely as a read-only manifest of blocks to copy.
• always -- The bitmap is always synchronized with the operation, regardless of whether or not the operation was successful.

An enumeration whose values tell the mirror block job when to trigger writes to the target.

Values

• background -- copy data in background only.
• write-blocking -- when data is written to the source, write it (synchronously) to the target as well.  In addition, data is copied in background just like in background mode.

Information specific to mirror block jobs.

Members

• actively-synced (boolean) -- Whether the source is actively synced to the target, i.e. same data and new writes are done synchronously to both.

Information about a long-running block device operation.

Members

• type (JobType) -- the job type ('stream' for image streaming)
• device (string) -- The job identifier.  Originally the device name but other values are allowed since QEMU 2.7
• len (int) -- Estimated offset value at the completion of the job.  This value can arbitrarily change while the job is running, in both directions.
• offset (int) -- Progress made until now.  The unit is arbitrary and the value can only meaningfully be used for the ratio of offset to len.  The value is monotonically increasing.
• busy (boolean) -- false if the job is known to be in a quiescent state, with no pending I/O.  (Since 1.3)
• paused (boolean) -- whether the job is paused or, if busy is true, will pause itself as soon as possible.  (Since 1.3)
• speed (int) -- the rate limit, bytes per second
• io-status (BlockDeviceIoStatus) -- the status of the job (since 1.3)
• ready (boolean) -- true if the job may be completed (since 2.2)
• status (JobStatus) -- Current job state/status (since 2.12)
• auto-finalize (boolean) -- Job will finalize itself when PENDING, moving to the CONCLUDED state.  (since 2.12)
• auto-dismiss (boolean) -- Job will dismiss itself when CONCLUDED, moving to the NULL state and disappearing from the query list.  (since 2.12)
• error (string, optional) -- Error information if the job did not complete successfully. Not set if the job completed successfully.  (since 2.12.1)
• When type is mirror: The members of BlockJobInfoMirror.

Return information about long-running block device operations.

Return

[BlockJobInfo] -- a list of BlockJobInfo for each active block job

Resize a block image while a guest is running.

Either device or node-name must be set but not both.

Arguments

• device (string, optional) -- the name of the device to get the image resized
• node-name (string, optional) -- graph node name to get the image resized (Since 2.0)
• size (int) -- new image size in bytes

Errors

• If device is not a valid block device, DeviceNotFound

Example:

-> { "execute": "block_resize",
     "arguments": { "device": "scratch", "size": 1073741824 } }
<- { "return": {} }

An enumeration that tells QEMU how to set the backing file path in a new image file.

Values

• existing -- QEMU should look for an existing image file.
• absolute-paths -- QEMU should create a new image with absolute paths for the backing file.  If there is no backing file available, the new image will not be backed either.

Either device or node-name must be set but not both.

Members

• device (string, optional) -- the name of the device to take a snapshot of.
• node-name (string, optional) -- graph node name to generate the snapshot from (Since 2.0)
• snapshot-file (string) -- the target of the new overlay image.  If the file exists, or if it is a device, the overlay will be created in the existing file/device.  Otherwise, a new file will be created.
• snapshot-node-name (string, optional) -- the graph node name of the new image (Since 2.0)
• format (string, optional) -- the format of the overlay image, default is 'qcow2'.
• mode (NewImageMode, optional) -- whether and how QEMU should create a new image, default is 'absolute-paths'.

Members

• node (string) -- device or node name that will have a snapshot taken.
• overlay (string) -- reference to the existing block device that will become the overlay of node, as part of taking the snapshot.  It must not have a current backing file (this can be achieved by passing "backing": null to blockdev-add).

Optional parameters for backup.  These parameters don't affect functionality, but may significantly affect performance.

Members

• use-copy-range (boolean, optional) -- Use copy offloading.  Default false.
• max-workers (int, optional) -- Maximum number of parallel requests for the sustained background copying process.  Doesn't influence copy-before-write operations.  Default 64.
• max-chunk (int, optional) -- Maximum request length for the sustained background copying process.  Doesn't influence copy-before-write operations.  0 means unlimited.  If max-chunk is non-zero then it should not be less than job cluster size which is calculated as maximum of target image cluster size and 64k.  Default 0.
• min-cluster-size (int, optional) -- Minimum size of blocks used by copy-before-write and background copy operations.  Has to be a power of 2.  No effect if smaller than the maximum of the target's cluster size and 64 KiB.  Default 0.  (Since 9.2)

Members

• job-id (string, optional) -- identifier for the newly-created block job.  If omitted, the device name will be used.  (Since 2.7)
• device (string) -- the device name or node-name of a root node which should be copied.
• sync (MirrorSyncMode) -- what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, from a dirty bitmap, or only new I/O).
• speed (int, optional) -- the maximum speed, in bytes per second.  The default is 0, for unlimited.
• bitmap (string, optional) -- The name of a dirty bitmap to use.  Must be present if sync is "bitmap" or "incremental".  Can be present if sync is "full" or "top".  Must not be present otherwise. (Since 2.4 (drive-backup), 3.1 (blockdev-backup))
• bitmap-mode (BitmapSyncMode, optional) -- Specifies the type of data the bitmap should contain after the operation concludes.  Must be present if a bitmap was provided, Must NOT be present otherwise.  (Since 4.2)
• compress (boolean, optional) -- true to compress data, if the target format supports it. (default: false) (since 2.8)
• on-source-error (BlockdevOnError, optional) -- the action to take on an error on the source, default 'report'.  'stop' and 'enospc' can only be used if the block device supports io-status (see BlockInfo).
• on-target-error (BlockdevOnError, optional) -- the action to take on an error on the target, default 'report' (no limitations, since this applies to a different block device than device).
• auto-finalize (boolean, optional) -- When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes.  When true, this job will automatically perform its abort or commit actions.  Defaults to true.  (Since 2.12)
• auto-dismiss (boolean, optional) -- When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss.  When true, this job will automatically disappear from the query list without user intervention. Defaults to true.  (Since 2.12)
• filter-node-name (string, optional) -- the node name that should be assigned to the filter driver that the backup job inserts into the graph above node specified by drive.  If this option is not given, a node name is autogenerated.  (Since: 4.2)
• discard-source (boolean, optional) -- Discard blocks on source which have already been copied to the target.  (Since 9.1)
• x-perf (BackupPerf, optional) -- Performance options.  (Since 6.0)

Features

• unstable -- Member x-perf is experimental.

NOTE:

on-source-error and on-target-error only affect background I/O.  If an error occurs during a guest write request, the device's rerror/werror actions will be used.

Members

• target (string) -- the target of the new image.  If the file exists, or if it is a device, the existing file/device will be used as the new destination.  If it does not exist, a new file will be created.
• format (string, optional) -- the format of the new destination, default is to probe if mode is 'existing', else the format of the source
• mode (NewImageMode, optional) -- whether and how QEMU should create a new image, default is 'absolute-paths'.
• The members of BackupCommon.

Members

• target (string) -- the device name or node-name of the backup target node.
• The members of BackupCommon.

Takes a synchronous snapshot of a block device.

Arguments

• The members of BlockdevSnapshotSync.

Errors

• If device is not a valid block device, DeviceNotFound

Example:

-> { "execute": "blockdev-snapshot-sync",
     "arguments": { "device": "ide-hd0",
                    "snapshot-file":
                    "/some/place/my-image",
                    "format": "qcow2" } }
<- { "return": {} }

Takes a snapshot of a block device.

Take a snapshot, by installing 'node' as the backing image of 'overlay'.  Additionally, if 'node' is associated with a block device, the block device changes to using 'overlay' as its new active image.

Arguments

• The members of BlockdevSnapshot.

Features

• allow-write-only-overlay -- If present, the check whether this operation is safe was relaxed so that it can be used to change backing file of a destination of a blockdev-mirror.  (since 5.0)

Example:

-> { "execute": "blockdev-add",
     "arguments": { "driver": "qcow2",
                    "node-name": "node1534",
                    "file": { "driver": "file",
                              "filename": "hd1.qcow2" },
                    "backing": null } }

<- { "return": {} }

-> { "execute": "blockdev-snapshot",
     "arguments": { "node": "ide-hd0",
                    "overlay": "node1534" } }
<- { "return": {} }

Change the backing file in the image file metadata.  This does not cause QEMU to reopen the image file to reparse the backing filename (it may, however, perform a reopen to change permissions from r/o -> r/w -> r/o, if needed).  The new backing file string is written into the image file metadata, and the QEMU internal strings are updated.

Arguments

• image-node-name (string) -- The name of the block driver state node of the image to modify.  The "device" argument is used to verify "image-node-name" is in the chain described by "device".
• device (string) -- The device name or node-name of the root node that owns image-node-name.
• backing-file (string) -- The string to write as the backing file.  This string is not validated, so care should be taken when specifying the string or the image chain may not be able to be reopened again.

Errors

• If "device" does not exist or cannot be determined, DeviceNotFound

Live commit of data from overlay image nodes into backing nodes - i.e., writes data between 'top' and 'base' into 'base'.

If top == base, that is an error.  If top has no overlays on top of it, or if it is in use by a writer, the job will not be completed by itself.  The user needs to complete the job with the block-job-complete command after getting the ready event.  (Since 2.0)

If the base image is smaller than top, then the base image will be resized to be the same size as top.  If top is smaller than the base image, the base will not be truncated.  If you want the base image size to match the size of the smaller top, you can safely truncate it yourself once the commit operation successfully completes.

Arguments

• job-id (string, optional) -- identifier for the newly-created block job.  If omitted, the device name will be used.  (Since 2.7)
• device (string) -- the device name or node-name of a root node
• base-node (string, optional) -- The node name of the backing image to write data into. If not specified, this is the deepest backing image. (since: 3.1)
• base (string, optional) -- Same as base-node, except that it is a file name rather than a node name.  This must be the exact filename string that was used to open the node; other strings, even if addressing the same file, are not accepted
• top-node (string, optional) -- The node name of the backing image within the image chain which contains the topmost data to be committed down.  If not specified, this is the active layer.  (since: 3.1)
• top (string, optional) -- Same as top-node, except that it is a file name rather than a node name.  This must be the exact filename string that was used to open the node; other strings, even if addressing the same file, are not accepted

• backing-file (string, optional) --

  The backing file string to write into the overlay image of 'top'.  If 'top' does not have an overlay image, or if 'top' is in use by a writer, specifying a backing file string is an error.

  This filename is not validated.  If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.

  If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol.  (Since 2.1)

• backing-mask-protocol (boolean, optional) -- If true, replace any protocol mentioned in the 'backing file format' with 'raw', rather than storing the protocol name as the backing format.  Can be used even when no image header will be updated (default false; since 9.0).
• speed (int, optional) -- the maximum speed, in bytes per second
• on-error (BlockdevOnError, optional) -- the action to take on an error.  'ignore' means that the request should be retried.  (default: report; Since: 5.0)
• filter-node-name (string, optional) -- the node name that should be assigned to the filter driver that the commit job inserts into the graph above top.  If this option is not given, a node name is autogenerated.  (Since: 2.9)
• auto-finalize (boolean, optional) -- When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes.  When true, this job will automatically perform its abort or commit actions.  Defaults to true.  (Since 3.1)
• auto-dismiss (boolean, optional) -- When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss.  When true, this job will automatically disappear from the query list without user intervention. Defaults to true.  (Since 3.1)

Features

• deprecated -- Members base and top are deprecated.  Use base-node and top-node instead.

Errors

• If device does not exist, DeviceNotFound

Example:

-> { "execute": "block-commit",
     "arguments": { "device": "virtio0",
                    "top": "/tmp/snap1.qcow2" } }
<- { "return": {} }

This command is deprecated.

Start a point-in-time copy of a block device to a new destination. The status of ongoing drive-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value 'backup'.  The operation can be stopped before it has completed using the block-job-cancel command.

Arguments

• The members of DriveBackup.

Features

• deprecated -- This command is deprecated.  Use blockdev-backup instead.

Errors

• If device is not a valid block device, GenericError

Example:

-> { "execute": "drive-backup",
     "arguments": { "device": "drive0",
                    "sync": "full",
                    "target": "backup.img" } }
<- { "return": {} }

Start a point-in-time copy of a block device to a new destination. The status of ongoing blockdev-backup operations can be checked with query-block-jobs where the BlockJobInfo.type field has the value 'backup'.  The operation can be stopped before it has completed using the block-job-cancel command.

Arguments

• The members of BlockdevBackup.

Errors

• If device is not a valid block device, DeviceNotFound

Example:

-> { "execute": "blockdev-backup",
     "arguments": { "device": "src-id",
                    "sync": "full",
                    "target": "tgt-id" } }
<- { "return": {} }

Get the named block driver list

Arguments

• flat (boolean, optional) -- Omit the nested data about backing image ("backing-image" key) if true.  Default is false (Since 5.0)

Return

[BlockDeviceInfo] -- the list of BlockDeviceInfo

Example:

-> { "execute": "query-named-block-nodes" }
<- { "return": [ { "ro":false,
                   "drv":"qcow2",
                   "encrypted":false,
                   "file":"disks/test.qcow2",
                   "node-name": "my-node",
                   "backing_file_depth":1,
                   "detect_zeroes":"off",
                   "bps":1000000,
                   "bps_rd":0,
                   "bps_wr":0,
                   "iops":1000000,
                   "iops_rd":0,
                   "iops_wr":0,
                   "bps_max": 8000000,
                   "bps_rd_max": 0,
                   "bps_wr_max": 0,
                   "iops_max": 0,
                   "iops_rd_max": 0,
                   "iops_wr_max": 0,
                   "iops_size": 0,
                   "write_threshold": 0,
                   "image":{
                      "filename":"disks/test.qcow2",
                      "format":"qcow2",
                      "virtual-size":2048000,
                      "backing_file":"base.qcow2",
                      "full-backing-filename":"disks/base.qcow2",
                      "backing-filename-format":"qcow2",
                      "snapshots":[
                         {
                            "id": "1",
                            "name": "snapshot1",
                            "vm-state-size": 0,
                            "date-sec": 10000200,
                            "date-nsec": 12,
                            "vm-clock-sec": 206,
                            "vm-clock-nsec": 30
                         }
                      ],
                      "backing-image":{
                          "filename":"disks/base.qcow2",
                          "format":"qcow2",
                          "virtual-size":2048000
                      }
                   } } ] }

Values

• block-backend -- corresponds to BlockBackend
• block-job -- corresponds to BlockJob
• block-driver -- corresponds to BlockDriverState

Members

• id (int) -- Block graph node identifier.  This id is generated only for x-debug-query-block-graph and does not relate to any other identifiers in Qemu.
• type (XDbgBlockGraphNodeType) -- Type of graph node.  Can be one of block-backend, block-job or block-driver-state.
• name (string) -- Human readable name of the node.  Corresponds to node-name for block-driver-state nodes; is not guaranteed to be unique in the whole graph (with block-jobs and block-backends).

Enum of base block permissions.

Values

• consistent-read -- A user that has the "permission" of consistent reads is guaranteed that their view of the contents of the block device is complete and self-consistent, representing the contents of a disk at a specific point.  For most block devices (including their backing files) this is true, but the property cannot be maintained in a few situations like for intermediate nodes of a commit block job.
• write -- This permission is required to change the visible disk contents.
• write-unchanged -- This permission (which is weaker than BLK_PERM_WRITE) is both enough and required for writes to the block node when the caller promises that the visible disk content doesn't change.  As the BLK_PERM_WRITE permission is strictly stronger, either is sufficient to perform an unchanging write.
• resize -- This permission is required to change the size of a block node.

Block Graph edge description for x-debug-query-block-graph.

Members

• parent (int) -- parent id
• child (int) -- child id
• name (string) -- name of the relation (examples are 'file' and 'backing')
• perm ([BlockPermission]) -- granted permissions for the parent operating on the child
• shared-perm ([BlockPermission]) -- permissions that can still be granted to other users of the child while it is still attached to this parent

Block Graph - list of nodes and list of edges.

Members

• nodes ([XDbgBlockGraphNode]) -- Not documented
• edges ([XDbgBlockGraphEdge]) -- Not documented

This command is unstable/experimental.

Get the block graph.

Features

• unstable -- This command is meant for debugging.

Start mirroring a block device's writes to a new destination. target specifies the target of the new image.  If the file exists, or if it is a device, it will be used as the new destination for writes.  If it does not exist, a new file will be created.  format specifies the format of the mirror image, default is to probe if mode='existing', else the format of the source.

Arguments

• The members of DriveMirror.

Errors

• If device is not a valid block device, GenericError

Example:

-> { "execute": "drive-mirror",
     "arguments": { "device": "ide-hd0",
                    "target": "/some/place/my-image",
                    "sync": "full",
                    "format": "qcow2" } }
<- { "return": {} }

A set of parameters describing drive mirror setup.

Members

• job-id (string, optional) -- identifier for the newly-created block job.  If omitted, the device name will be used.  (Since 2.7)
• device (string) -- the device name or node-name of a root node whose writes should be mirrored.
• target (string) -- the target of the new image.  If the file exists, or if it is a device, the existing file/device will be used as the new destination.  If it does not exist, a new file will be created.
• format (string, optional) -- the format of the new destination, default is to probe if mode is 'existing', else the format of the source
• node-name (string, optional) -- the new block driver state node name in the graph (Since 2.1)
• replaces (string, optional) -- with sync=full graph node name to be replaced by the new image when a whole image copy is done.  This can be used to repair broken Quorum files.  By default, device is replaced, although implicitly created filters on it are kept.  (Since 2.1)
• mode (NewImageMode, optional) -- whether and how QEMU should create a new image, default is 'absolute-paths'.
• speed (int, optional) -- the maximum speed, in bytes per second
• sync (MirrorSyncMode) -- what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).
• granularity (int, optional) -- granularity of the dirty bitmap, default is 64K if the image format doesn't have clusters, 4K if the clusters are smaller than that, else the cluster size.  Must be a power of 2 between 512 and 64M (since 1.4).
• buf-size (int, optional) -- maximum amount of data in flight from source to target (since 1.4).
• on-source-error (BlockdevOnError, optional) -- the action to take on an error on the source, default 'report'.  'stop' and 'enospc' can only be used if the block device supports io-status (see BlockInfo).
• on-target-error (BlockdevOnError, optional) -- the action to take on an error on the target, default 'report' (no limitations, since this applies to a different block device than device).
• unmap (boolean, optional) -- Whether to try to unmap target sectors where source has only zero.  If true, and target unallocated sectors will read as zero, target image sectors will be unmapped; otherwise, zeroes will be written.  Both will result in identical contents. Default is true.  (Since 2.4)
• copy-mode (MirrorCopyMode, optional) -- when to copy data to the destination; defaults to 'background' (Since: 3.0)
• auto-finalize (boolean, optional) -- When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes.  When true, this job will automatically perform its abort or commit actions.  Defaults to true.  (Since 3.1)
• auto-dismiss (boolean, optional) -- When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss.  When true, this job will automatically disappear from the query list without user intervention. Defaults to true.  (Since 3.1)

Members

• node (string) -- name of device/node which the bitmap is tracking
• name (string) -- name of the dirty bitmap

Members

• node (string) -- name of device/node which the bitmap is tracking
• name (string) -- name of the dirty bitmap (must be less than 1024 bytes)
• granularity (int, optional) -- the bitmap granularity, default is 64k for block-dirty-bitmap-add
• persistent (boolean, optional) -- the bitmap is persistent, i.e. it will be saved to the corresponding block device image file on its close.  For now only Qcow2 disks support persistent bitmaps.  Default is false for block-dirty-bitmap-add.  (Since: 2.10)
• disabled (boolean, optional) -- the bitmap is created in the disabled state, which means that it will not track drive changes.  The bitmap may be enabled with block-dirty-bitmap-enable.  Default is false.  (Since: 4.0)

Alternatives

• local (string) -- name of the bitmap, attached to the same node as target bitmap.
• external (BlockDirtyBitmap) -- bitmap with specified node

Members

• node (string) -- name of device/node which the target bitmap is tracking
• target (string) -- name of the destination dirty bitmap
• bitmaps ([BlockDirtyBitmapOrStr]) -- name(s) of the source dirty bitmap(s) at node and/or fully specified BlockDirtyBitmap elements.  The latter are supported since 4.1.

Create a dirty bitmap with a name on the node, and start tracking the writes.

Arguments

• The members of BlockDirtyBitmapAdd.

Errors

• If node is not a valid block device or node, DeviceNotFound
• If name is already taken, GenericError

Example:

-> { "execute": "block-dirty-bitmap-add",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

Stop write tracking and remove the dirty bitmap that was created with block-dirty-bitmap-add.  If the bitmap is persistent, remove it from its storage too.

Arguments

• The members of BlockDirtyBitmap.

Errors

• If node is not a valid block device or node, DeviceNotFound
• If name is not found, GenericError
• if name is frozen by an operation, GenericError

Example:

-> { "execute": "block-dirty-bitmap-remove",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

Clear (reset) a dirty bitmap on the device, so that an incremental backup from this point in time forward will only backup clusters modified after this clear operation.

Arguments

• The members of BlockDirtyBitmap.

Errors

• If node is not a valid block device, DeviceNotFound
• If name is not found, GenericError

Example:

-> { "execute": "block-dirty-bitmap-clear",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

Enables a dirty bitmap so that it will begin tracking disk changes.

Arguments

• The members of BlockDirtyBitmap.

Errors

• If node is not a valid block device, DeviceNotFound
• If name is not found, GenericError

Example:

-> { "execute": "block-dirty-bitmap-enable",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

Disables a dirty bitmap so that it will stop tracking disk changes.

Arguments

• The members of BlockDirtyBitmap.

Errors

• If node is not a valid block device, DeviceNotFound
• If name is not found, GenericError

Example:

-> { "execute": "block-dirty-bitmap-disable",
     "arguments": { "node": "drive0", "name": "bitmap0" } }
<- { "return": {} }

Merge dirty bitmaps listed in bitmaps to the target dirty bitmap. Dirty bitmaps in bitmaps will be unchanged, except if it also appears as the target bitmap.  Any bits already set in target will still be set after the merge, i.e., this operation does not clear the target.  On error, target is unchanged.

The resulting bitmap will count as dirty any clusters that were dirty in any of the source bitmaps.  This can be used to achieve backup checkpoints, or in simpler usages, to copy bitmaps.

Arguments

• The members of BlockDirtyBitmapMerge.

Errors

• If node is not a valid block device, DeviceNotFound
• If any bitmap in bitmaps or target is not found, GenericError
• If any of the bitmaps have different sizes or granularities, GenericError

Example:

-> { "execute": "block-dirty-bitmap-merge",
     "arguments": { "node": "drive0", "target": "bitmap0",
                    "bitmaps": ["bitmap1"] } }
<- { "return": {} }

SHA256 hash of dirty bitmap data

Members

• sha256 (string) -- ASCII representation of SHA256 bitmap hash

This command is unstable/experimental.

Get bitmap SHA256.

Arguments

• The members of BlockDirtyBitmap.

Features

• unstable -- This command is meant for debugging.

Return

BlockDirtyBitmapSha256 -- BlockDirtyBitmapSha256

Errors

• If node is not a valid block device, DeviceNotFound
• If name is not found or if hashing has failed, GenericError

Start mirroring a block device's writes to a new destination.

Arguments

• job-id (string, optional) -- identifier for the newly-created block job.  If omitted, the device name will be used.  (Since 2.7)
• device (string) -- The device name or node-name of a root node whose writes should be mirrored.
• target (string) -- the id or node-name of the block device to mirror to.  This mustn't be attached to guest.
• replaces (string, optional) -- with sync=full graph node name to be replaced by the new image when a whole image copy is done.  This can be used to repair broken Quorum files.  By default, device is replaced, although implicitly created filters on it are kept.
• speed (int, optional) -- the maximum speed, in bytes per second
• sync (MirrorSyncMode) -- what parts of the disk image should be copied to the destination (all the disk, only the sectors allocated in the topmost image, or only new I/O).
• granularity (int, optional) -- granularity of the dirty bitmap, default is 64K if the image format doesn't have clusters, 4K if the clusters are smaller than that, else the cluster size.  Must be a power of 2 between 512 and 64M
• buf-size (int, optional) -- maximum amount of data in flight from source to target
• on-source-error (BlockdevOnError, optional) -- the action to take on an error on the source, default 'report'.  'stop' and 'enospc' can only be used if the block device supports io-status (see BlockInfo).
• on-target-error (BlockdevOnError, optional) -- the action to take on an error on the target, default 'report' (no limitations, since this applies to a different block device than device).
• filter-node-name (string, optional) -- the node name that should be assigned to the filter driver that the mirror job inserts into the graph above device.  If this option is not given, a node name is autogenerated.  (Since: 2.9)
• copy-mode (MirrorCopyMode, optional) -- when to copy data to the destination; defaults to 'background' (Since: 3.0)
• auto-finalize (boolean, optional) -- When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes.  When true, this job will automatically perform its abort or commit actions.  Defaults to true.  (Since 3.1)
• auto-dismiss (boolean, optional) -- When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss.  When true, this job will automatically disappear from the query list without user intervention. Defaults to true.  (Since 3.1)

Example:

-> { "execute": "blockdev-mirror",
     "arguments": { "device": "ide-hd0",
                    "target": "target0",
                    "sync": "full" } }
<- { "return": {} }

A set of parameters describing block throttling.

Members

• device (string, optional) -- Block device name
• id (string, optional) -- The name or QOM path of the guest device (since: 2.8)
• bps (int) -- total throughput limit in bytes per second
• bps_rd (int) -- read throughput limit in bytes per second
• bps_wr (int) -- write throughput limit in bytes per second
• iops (int) -- total I/O operations per second
• iops_rd (int) -- read I/O operations per second
• iops_wr (int) -- write I/O operations per second
• bps_max (int, optional) -- total throughput limit during bursts, in bytes (Since 1.7)
• bps_rd_max (int, optional) -- read throughput limit during bursts, in bytes (Since 1.7)
• bps_wr_max (int, optional) -- write throughput limit during bursts, in bytes (Since 1.7)
• iops_max (int, optional) -- total I/O operations per second during bursts, in bytes (Since 1.7)
• iops_rd_max (int, optional) -- read I/O operations per second during bursts, in bytes (Since 1.7)
• iops_wr_max (int, optional) -- write I/O operations per second during bursts, in bytes (Since 1.7)
• bps_max_length (int, optional) -- maximum length of the bps_max burst period, in seconds.  It must only be set if bps_max is set as well. Defaults to 1.  (Since 2.6)
• bps_rd_max_length (int, optional) -- maximum length of the bps_rd_max burst period, in seconds.  It must only be set if bps_rd_max is set as well. Defaults to 1.  (Since 2.6)
• bps_wr_max_length (int, optional) -- maximum length of the bps_wr_max burst period, in seconds.  It must only be set if bps_wr_max is set as well. Defaults to 1.  (Since 2.6)
• iops_max_length (int, optional) -- maximum length of the iops burst period, in seconds.  It must only be set if iops_max is set as well. Defaults to 1.  (Since 2.6)
• iops_rd_max_length (int, optional) -- maximum length of the iops_rd_max burst period, in seconds.  It must only be set if iops_rd_max is set as well.  Defaults to 1.  (Since 2.6)
• iops_wr_max_length (int, optional) -- maximum length of the iops_wr_max burst period, in seconds.  It must only be set if iops_wr_max is set as well.  Defaults to 1.  (Since 2.6)
• iops_size (int, optional) -- an I/O size in bytes (Since 1.7)
• group (string, optional) -- throttle group name (Since 2.4)

Features

• deprecated -- Member device is deprecated.  Use id instead.

Limit parameters for throttling.  Since some limit combinations are illegal, limits should always be set in one transaction.  All fields are optional.  When setting limits, if a field is missing the current value is not changed.

Members

• iops-total (int, optional) -- limit total I/O operations per second
• iops-total-max (int, optional) -- I/O operations burst
• iops-total-max-length (int, optional) -- length of the iops-total-max burst period, in seconds It must only be set if iops-total-max is set as well.
• iops-read (int, optional) -- limit read operations per second
• iops-read-max (int, optional) -- I/O operations read burst
• iops-read-max-length (int, optional) -- length of the iops-read-max burst period, in seconds It must only be set if iops-read-max is set as well.
• iops-write (int, optional) -- limit write operations per second
• iops-write-max (int, optional) -- I/O operations write burst
• iops-write-max-length (int, optional) -- length of the iops-write-max burst period, in seconds It must only be set if iops-write-max is set as well.
• bps-total (int, optional) -- limit total bytes per second
• bps-total-max (int, optional) -- total bytes burst
• bps-total-max-length (int, optional) -- length of the bps-total-max burst period, in seconds.  It must only be set if bps-total-max is set as well.
• bps-read (int, optional) -- limit read bytes per second
• bps-read-max (int, optional) -- total bytes read burst
• bps-read-max-length (int, optional) -- length of the bps-read-max burst period, in seconds It must only be set if bps-read-max is set as well.
• bps-write (int, optional) -- limit write bytes per second
• bps-write-max (int, optional) -- total bytes write burst
• bps-write-max-length (int, optional) -- length of the bps-write-max burst period, in seconds It must only be set if bps-write-max is set as well.
• iops-size (int, optional) -- when limiting by iops max size of an I/O in bytes

Properties for throttle-group objects.

Members

• limits (ThrottleLimits, optional) -- limits to apply for this throttle group
• x-iops-total (int, optional) -- Not documented
• x-iops-total-max (int, optional) -- Not documented
• x-iops-total-max-length (int, optional) -- Not documented
• x-iops-read (int, optional) -- Not documented
• x-iops-read-max (int, optional) -- Not documented
• x-iops-read-max-length (int, optional) -- Not documented
• x-iops-write (int, optional) -- Not documented
• x-iops-write-max (int, optional) -- Not documented
• x-iops-write-max-length (int, optional) -- Not documented
• x-bps-total (int, optional) -- Not documented
• x-bps-total-max (int, optional) -- Not documented
• x-bps-total-max-length (int, optional) -- Not documented
• x-bps-read (int, optional) -- Not documented
• x-bps-read-max (int, optional) -- Not documented
• x-bps-read-max-length (int, optional) -- Not documented
• x-bps-write (int, optional) -- Not documented
• x-bps-write-max (int, optional) -- Not documented
• x-bps-write-max-length (int, optional) -- Not documented
• x-iops-size (int, optional) -- Not documented

Features

• unstable -- All members starting with x- are aliases for the same key without x- in the limits object.  This is not a stable interface and may be removed or changed incompatibly in the future.  Use limits for a supported stable interface.

Copy data from a backing file into a block device.

The block streaming operation is performed in the background until the entire backing file has been copied.  This command returns immediately once streaming has started.  The status of ongoing block streaming operations can be checked with query-block-jobs.  The operation can be stopped before it has completed using the block-job-cancel command.

The node that receives the data is called the top image, can be located in any part of the chain (but always above the base image; see below) and can be specified using its device or node name. Earlier qemu versions only allowed 'device' to name the top level node; presence of the 'base-node' parameter during introspection can be used as a witness of the enhanced semantics of 'device'.

If a base file is specified then sectors are not copied from that base file and its backing chain.  This can be used to stream a subset of the backing file chain instead of flattening the entire image.  When streaming completes the image file will have the base file as its backing file, unless that node was changed while the job was running.  In that case, base's parent's backing (or filtered, whichever exists) child (i.e., base at the beginning of the job) will be the new backing file.

On successful completion the image file is updated to drop the backing file and the BLOCK_JOB_COMPLETED event is emitted.

In case device is a filter node, block-stream modifies the first non-filter overlay node below it to point to the new backing node instead of modifying device itself.

Arguments

• job-id (string, optional) -- identifier for the newly-created block job.  If omitted, the device name will be used.  (Since 2.7)
• device (string) -- the device or node name of the top image
• base (string, optional) -- the common backing file name.  It cannot be set if base-node or bottom is also set.
• base-node (string, optional) -- the node name of the backing file.  It cannot be set if base or bottom is also set.  (Since 2.8)
• bottom (string, optional) -- the last node in the chain that should be streamed into top.  It cannot be set if base or base-node is also set.  It cannot be filter node.  (Since 6.0)

• backing-file (string, optional) --

  The backing file string to write into the top image. This filename is not validated.

  If a pathname string is such that it cannot be resolved by QEMU, that means that subsequent QMP or HMP commands must use node-names for the image in question, as filename lookup methods will fail.

  If not specified, QEMU will automatically determine the backing file string to use, or error out if there is no obvious choice. Care should be taken when specifying the string, to specify a valid filename or protocol.  (Since 2.1)

• backing-mask-protocol (boolean, optional) -- If true, replace any protocol mentioned in the 'backing file format' with 'raw', rather than storing the protocol name as the backing format.  Can be used even when no image header will be updated (default false; since 9.0).
• speed (int, optional) -- the maximum speed, in bytes per second
• on-error (BlockdevOnError, optional) -- the action to take on an error (default report).  'stop' and 'enospc' can only be used if the block device supports io-status (see BlockInfo).  (Since 1.3)
• filter-node-name (string, optional) -- the node name that should be assigned to the filter driver that the stream job inserts into the graph above device.  If this option is not given, a node name is autogenerated.  (Since: 6.0)
• auto-finalize (boolean, optional) -- When false, this job will wait in a PENDING state after it has finished its work, waiting for block-job-finalize before making any block graph changes.  When true, this job will automatically perform its abort or commit actions.  Defaults to true.  (Since 3.1)
• auto-dismiss (boolean, optional) -- When false, this job will wait in a CONCLUDED state after it has completely ceased all work, and awaits block-job-dismiss.  When true, this job will automatically disappear from the query list without user intervention. Defaults to true.  (Since 3.1)

Errors

• If device does not exist, DeviceNotFound.

Example:

-> { "execute": "block-stream",
     "arguments": { "device": "virtio0",
                    "base": "/tmp/master.qcow2" } }
<- { "return": {} }

Set maximum speed for a background block operation.

This command can only be issued when there is an active block job.

Throttling can be disabled by setting the speed to 0.

Arguments

• device (string) -- The job identifier.  This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
• speed (int) -- the maximum speed, in bytes per second, or 0 for unlimited. Defaults to 0.

Errors

• If no background operation is active on this device, DeviceNotActive

Stop an active background block operation.

This command returns immediately after marking the active background block operation for cancellation.  It is an error to call this command if no operation is in progress.

The operation will cancel as soon as possible and then emit the BLOCK_JOB_CANCELLED event.  Before that happens the job is still visible when enumerated using query-block-jobs.

Note that if you issue 'block-job-cancel' after 'drive-mirror' has indicated (via the event BLOCK_JOB_READY) that the source and destination are synchronized, then the event triggered by this command changes to BLOCK_JOB_COMPLETED, to indicate that the mirroring has ended and the destination now has a point-in-time copy tied to the time of the cancellation.

For streaming, the image file retains its backing file unless the streaming operation happens to complete just as it is being cancelled.  A new streaming operation can be started at a later time to finish copying all data from the backing file.

Arguments

• device (string) -- The job identifier.  This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.
• force (boolean, optional) -- If true, and the job has already emitted the event BLOCK_JOB_READY, abandon the job immediately (even if it is paused) instead of waiting for the destination to complete its final synchronization (since 1.3)

Errors

• If no background operation is active on this device, DeviceNotActive

Pause an active background block operation.

This command returns immediately after marking the active background block operation for pausing.  It is an error to call this command if no operation is in progress or if the job is already paused.

The operation will pause as soon as possible.  No event is emitted when the operation is actually paused.  Cancelling a paused job automatically resumes it.

Arguments

• device (string) -- The job identifier.  This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Errors

• If no background operation is active on this device, DeviceNotActive

Resume an active background block operation.

This command returns immediately after resuming a paused background block operation.  It is an error to call this command if no operation is in progress or if the job is not paused.

This command also clears the error status of the job.

Arguments

• device (string) -- The job identifier.  This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Errors

• If no background operation is active on this device, DeviceNotActive

Manually trigger completion of an active background block operation. This is supported for drive mirroring, where it also switches the device to write to the target path only.  The ability to complete is signaled with a BLOCK_JOB_READY event.

This command completes an active background block operation synchronously.  The ordering of this command's return with the BLOCK_JOB_COMPLETED event is not defined.  Note that if an I/O error occurs during the processing of this command: 1) the command itself will fail; 2) the error will be processed according to the rerror/werror arguments that were specified when starting the operation.

A cancelled or paused job cannot be completed.

Arguments

• device (string) -- The job identifier.  This used to be a device name (hence the name of the parameter), but since QEMU 2.7 it can have other values.

Errors

• If no background operation is active on this device, DeviceNotActive

For jobs that have already concluded, remove them from the block-job-query list.  This command only needs to be run for jobs which were started with QEMU 2.12+ job lifetime management semantics.

This command will refuse to operate on any job that has not yet reached its terminal state, JOB_STATUS_CONCLUDED.  For jobs that make use of the BLOCK_JOB_READY event, block-job-cancel or block-job-complete will still need to be used as appropriate.

Arguments

• id (string) -- The job identifier.

Once a job that has manual=true reaches the pending state, it can be instructed to finalize any graph changes and do any necessary cleanup via this command.  For jobs in a transaction, instructing one job to finalize will force ALL jobs in the transaction to finalize, so it is only necessary to instruct a single member job to finalize.

Arguments

• id (string) -- The job identifier.

Members

• copy-mode (MirrorCopyMode) -- Switch to this copy mode.  Currently, only the switch from 'background' to 'write-blocking' is implemented.

Block job options that can be changed after job creation.

Members

• id (string) -- The job identifier
• type (JobType) -- The job type
• When type is mirror: The members of BlockJobChangeOptionsMirror.

Change the block job's options.

Arguments

• The members of BlockJobChangeOptions.

Determines how to handle discard requests.

Values

• ignore -- Ignore the request
• unmap -- Forward as an unmap request

Describes the operation mode for the automatic conversion of plain zero writes by the OS to driver specific optimized zero write commands.

Values

• off -- Disabled (default)
• on -- Enabled
• unmap -- Enabled and even try to unmap blocks if possible.  This requires also that BlockdevDiscardOptions is set to unmap for this device.

Selects the AIO backend to handle I/O requests

Values

• threads -- Use qemu's thread pool
• native -- Use native AIO backend (only Linux and Windows)
• io_uring -- Use linux io_uring (since 5.0)

Includes cache-related options for block devices

Members

• direct (boolean, optional) -- enables use of O_DIRECT (bypass the host page cache; default: false)
• no-flush (boolean, optional) -- ignore any flush requests for the device (default: false)

Drivers that are supported in block device operations.

Values

• throttle -- Since 2.11
• nvme -- Since 2.12
• copy-on-read -- Since 3.0
• blklogwrites -- Since 3.0
• blkreplay -- Since 4.2
• compress -- Since 5.0
• copy-before-write -- Since 6.2
• snapshot-access -- Since 7.0
• blkdebug -- Not documented
• blkverify -- Not documented
• bochs -- Not documented
• cloop -- Not documented
• dmg -- Not documented
• file -- Not documented
• ftp -- Not documented
• ftps -- Not documented
• gluster -- Not documented
• host_cdrom -- Not documented
• host_device -- Not documented
• http -- Not documented
• https -- Not documented
• io_uring -- Not documented
• iscsi -- Not documented
• luks -- Not documented
• nbd -- Not documented
• nfs -- Not documented
• null-aio -- Not documented
• null-co -- Not documented
• nvme-io_uring -- Not documented
• parallels -- Not documented
• preallocate -- Not documented
• qcow -- Not documented
• qcow2 -- Not documented
• qed -- Not documented
• quorum -- Not documented
• raw -- Not documented
• rbd -- Not documented
• replication -- Not documented
• ssh -- Not documented
• vdi -- Not documented
• vhdx -- Not documented
• virtio-blk-vfio-pci -- Not documented
• virtio-blk-vhost-user -- Not documented
• virtio-blk-vhost-vdpa -- Not documented
• vmdk -- Not documented
• vpc -- Not documented
• vvfat -- Not documented

Features

• deprecated -- Member gluster is deprecated because GlusterFS development ceased.

Driver specific block device options for the file backend.

Members

• filename (string) -- path to the image file
• pr-manager (string, optional) -- the id for the object that will handle persistent reservations for this device (default: none, forward the commands via SG_IO; since 2.11)
• aio (BlockdevAioOptions, optional) -- AIO backend (default: threads) (since: 2.8)
• aio-max-batch (int, optional) -- maximum number of requests to batch together into a single submission in the AIO backend.  The smallest value between this and the aio-max-batch value of the IOThread object is chosen.  0 means that the AIO backend will handle it automatically.  (default: 0, since 6.2)
• locking (OnOffAuto, optional) -- whether to enable file locking.  If set to 'auto', only enable when Open File Descriptor (OFD) locking API is available (default: auto, since 2.10)
• drop-cache (boolean, optional) -- invalidate page cache during live migration.  This prevents stale data on the migration destination with cache.direct=off.  Currently only supported on Linux hosts. (default: on, since: 4.0)
• x-check-cache-dropped (boolean, optional) -- whether to check that page cache was dropped on live migration.  May cause noticeable delays if the image file is large, do not use in production.  (default: off) (since: 3.0)

Features

• dynamic-auto-read-only -- If present, enabled auto-read-only means that the driver will open the image read-only at first, dynamically reopen the image file read-write when the first writer is attached to the node and reopen read-only when the last writer is detached.  This allows giving QEMU write permissions only on demand when an operation actually needs write access.
• unstable -- Member x-check-cache-dropped is meant for debugging.

Driver specific block device options for the null backend.

Members

• size (int, optional) -- size of the device in bytes.
• latency-ns (int, optional) -- emulated latency (in nanoseconds) in processing requests.  Default to zero which completes requests immediately. (Since 2.4)
• read-zeroes (boolean, optional) -- if true, reads from the device produce zeroes; if false, the buffer is left unchanged. (default: false; since: 4.1)

Driver specific block device options for the NVMe backend.

Members

• device (string) -- PCI controller address of the NVMe device in format hhhh:bb:ss.f (host:bus:slot.function)
• namespace (int) -- namespace number of the device, starting from 1.

Note that the PCI device must have been unbound from any host kernel driver before instructing QEMU to add the blockdev.

Driver specific block device options for the vvfat protocol.

Members

• dir (string) -- directory to be exported as FAT image
• fat-type (int, optional) -- FAT type: 12, 16 or 32
• floppy (boolean, optional) -- whether to export a floppy image (true) or partitioned hard disk (false; default)
• label (string, optional) -- set the volume label, limited to 11 bytes.  FAT16 and FAT32 traditionally have some restrictions on labels, which are ignored by most operating systems.  Defaults to "QEMU VVFAT". (since 2.4)
• rw (boolean, optional) -- whether to allow write operations (default: false)

Driver specific block device options for image format that have no option besides their data source.

Members

• file (BlockdevRef) -- reference to or definition of the data source block device

Driver specific block device options for LUKS.

Members

• key-secret (string, optional) -- the ID of a QCryptoSecret object providing the decryption key (since 2.6).  Mandatory except when doing a metadata-only probe of the image.
• header (BlockdevRef, optional) -- block device holding a detached LUKS header.  (since 9.0)
• The members of BlockdevOptionsGenericFormat.

Driver specific block device options for image format that have no option besides their data source and an optional backing file.

Members

• backing (BlockdevRefOrNull, optional) -- reference to or definition of the backing file block device, null disables the backing file entirely.  Defaults to the backing file stored the image file.
• The members of BlockdevOptionsGenericFormat.

General overlap check modes.

Values

• none -- Do not perform any checks
• constant -- Perform only checks which can be done in constant time and without reading anything from disk
• cached -- Perform only checks which can be done without reading anything from disk
• all -- Perform all available overlap checks

Structure of flags for each metadata structure.  Setting a field to 'true' makes QEMU guard that Qcow2 format structure against unintended overwriting.  See Qcow2 format specification for detailed information on these structures.  The default value is chosen according to the template given.

Members

• template (Qcow2OverlapCheckMode, optional) -- Specifies a template mode which can be adjusted using the other flags, defaults to 'cached'
• main-header (boolean, optional) -- Qcow2 format header
• active-l1 (boolean, optional) -- Qcow2 active L1 table
• active-l2 (boolean, optional) -- Qcow2 active L2 table
• refcount-table (boolean, optional) -- Qcow2 refcount table
• refcount-block (boolean, optional) -- Qcow2 refcount blocks
• snapshot-table (boolean, optional) -- Qcow2 snapshot table
• inactive-l1 (boolean, optional) -- Qcow2 inactive L1 tables
• inactive-l2 (boolean, optional) -- Qcow2 inactive L2 tables
• bitmap-directory (boolean, optional) -- Qcow2 bitmap directory (since 3.0)

Specifies which metadata structures should be guarded against unintended overwriting.

Alternatives

• flags (Qcow2OverlapCheckFlags) -- set of flags for separate specification of each metadata structure type
• mode (Qcow2OverlapCheckMode) -- named mode which chooses a specific set of flags

Values

• aes -- AES-CBC with plain64 initialization vectors

Members

• format (BlockdevQcowEncryptionFormat) -- encryption format
• When format is aes: The members of QCryptoBlockOptionsQCow.

Driver specific block device options for qcow.

Members

• encrypt (BlockdevQcowEncryption, optional) -- Image decryption options.  Mandatory for encrypted images, except when doing a metadata-only probe of the image.
• The members of BlockdevOptionsGenericCOWFormat.

Values

• aes -- AES-CBC with plain64 initialization vectors
• luks -- Not documented

Members

• format (BlockdevQcow2EncryptionFormat) -- encryption format
• When format is aes: The members of QCryptoBlockOptionsQCow.
• When format is luks: The members of QCryptoBlockOptionsLUKS.

Filter driver intended to be inserted between format and protocol node and do preallocation in protocol node on write.

Members

• prealloc-align (int, optional) -- on preallocation, align file length to this number, default 1048576 (1M)
• prealloc-size (int, optional) -- how much to preallocate, default 134217728 (128M)
• The members of BlockdevOptionsGenericFormat.

Driver specific block device options for qcow2.

Members

• lazy-refcounts (boolean, optional) -- whether to enable the lazy refcounts feature (default is taken from the image file)
• pass-discard-request (boolean, optional) -- whether discard requests to the qcow2 device should be forwarded to the data source
• pass-discard-snapshot (boolean, optional) -- whether discard requests for the data source should be issued when a snapshot operation (e.g. deleting a snapshot) frees clusters in the qcow2 file
• pass-discard-other (boolean, optional) -- whether discard requests for the data source should be issued on other occasions where a cluster gets freed
• discard-no-unref (boolean, optional) -- when enabled, data clusters will remain preallocated when they are no longer used, e.g. because they are discarded or converted to zero clusters.  As usual, whether the old data is discarded or kept on the protocol level (i.e. in the image file) depends on the setting of the pass-discard-request option.  Keeping the clusters preallocated prevents qcow2 fragmentation that would otherwise be caused by freeing and re-allocating them later.  Besides potential performance degradation, such fragmentation can lead to increased allocation of clusters past the end of the image file, resulting in image files whose file length can grow much larger than their guest disk size would suggest.  If image file length is of concern (e.g. when storing qcow2 images directly on block devices), you should consider enabling this option.  (since 8.1)
• overlap-check (Qcow2OverlapChecks, optional) -- which overlap checks to perform for writes to the image, defaults to 'cached' (since 2.2)
• cache-size (int, optional) -- the maximum total size of the L2 table and refcount block caches in bytes (since 2.2)
• l2-cache-size (int, optional) -- the maximum size of the L2 table cache in bytes (since 2.2)
• l2-cache-entry-size (int, optional) -- the size of each entry in the L2 cache in bytes.  It must be a power of two between 512 and the cluster size.  The default value is the cluster size (since 2.12)
• refcount-cache-size (int, optional) -- the maximum size of the refcount block cache in bytes (since 2.2)
• cache-clean-interval (int, optional) -- clean unused entries in the L2 and refcount caches.  The interval is in seconds.  The default value is 600 on supporting platforms, and 0 on other platforms.  0 disables this feature.  (since 2.5)
• encrypt (BlockdevQcow2Encryption, optional) -- Image decryption options.  Mandatory for encrypted images, except when doing a metadata-only probe of the image.  (since 2.10)
• data-file (BlockdevRef, optional) -- reference to or definition of the external data file. This may only be specified for images that require an external data file.  If it is not specified for such an image, the data file name is loaded from the image file.  (since 4.0)
• The members of BlockdevOptionsGenericCOWFormat.

Values

• none -- Don't check the host key at all
• hash -- Compare the host key with a given hash
• known_hosts -- Check the host key against the known_hosts file

Values

• md5 -- The given hash is an md5 hash
• sha1 -- The given hash is an sha1 hash
• sha256 -- The given hash is an sha256 hash

Members

• type (SshHostKeyCheckHashType) -- The hash algorithm used for the hash
• hash (string) -- The expected hash value

Members

• mode (SshHostKeyCheckMode) -- How to check the host key
• When mode is hash: The members of SshHostKeyHash.

Members

• server (InetSocketAddress) -- host address
• path (string) -- path to the image on the host
• user (string, optional) -- user as which to connect, defaults to current local user name
• host-key-check (SshHostKeyCheck, optional) -- Defines how and what to check the host key against (default: known_hosts)

Trigger events supported by blkdebug.

Values

• l1_shrink_write_table -- write zeros to the l1 table to shrink image. (since 2.11)
• l1_shrink_free_l2_clusters -- discard the l2 tables.  (since 2.11)
• cor_write -- a write due to copy-on-read (since 2.11)
• cluster_alloc_space -- an allocation of file space for a cluster (since 4.1)
• none -- triggers once at creation of the blkdebug node (since 4.1)
• l1_update -- Not documented
• l1_grow_alloc_table -- Not documented
• l1_grow_write_table -- Not documented
• l1_grow_activate_table -- Not documented
• l2_load -- Not documented
• l2_update -- Not documented
• l2_update_compressed -- Not documented
• l2_alloc_cow_read -- Not documented
• l2_alloc_write -- Not documented
• read_aio -- Not documented
• read_backing_aio -- Not documented
• read_compressed -- Not documented
• write_aio -- Not documented
• write_compressed -- Not documented
• vmstate_load -- Not documented
• vmstate_save -- Not documented
• cow_read -- Not documented
• cow_write -- Not documented
• reftable_load -- Not documented
• reftable_grow -- Not documented
• reftable_update -- Not documented
• refblock_load -- Not documented
• refblock_update -- Not documented
• refblock_update_part -- Not documented
• refblock_alloc -- Not documented
• refblock_alloc_hookup -- Not documented
• refblock_alloc_write -- Not documented
• refblock_alloc_write_blocks -- Not documented
• refblock_alloc_write_table -- Not documented
• refblock_alloc_switch_table -- Not documented
• cluster_alloc -- Not documented
• cluster_alloc_bytes -- Not documented
• cluster_free -- Not documented
• flush_to_os -- Not documented
• flush_to_disk -- Not documented
• pwritev_rmw_head -- Not documented
• pwritev_rmw_after_head -- Not documented
• pwritev_rmw_tail -- Not documented
• pwritev_rmw_after_tail -- Not documented
• pwritev -- Not documented
• pwritev_zero -- Not documented
• pwritev_done -- Not documented
• empty_image_prepare -- Not documented

Kinds of I/O that blkdebug can inject errors in.

Values

• read -- .bdrv_co_preadv()
• write -- .bdrv_co_pwritev()
• write-zeroes -- .bdrv_co_pwrite_zeroes()
• discard -- .bdrv_co_pdiscard()
• flush -- .bdrv_co_flush_to_disk()
• block-status -- .bdrv_co_block_status()

Describes a single error injection for blkdebug.

Members

• event (BlkdebugEvent) -- trigger event
• state (int, optional) -- the state identifier blkdebug needs to be in to actually trigger the event; defaults to "any"
• iotype (BlkdebugIOType, optional) -- the type of I/O operations on which this error should be injected; defaults to "all read, write, write-zeroes, discard, and flush operations" (since: 4.1)
• errno (int, optional) -- error identifier (errno) to be returned; defaults to EIO
• sector (int, optional) -- specifies the sector index which has to be affected in order to actually trigger the event; defaults to "any sector"
• once (boolean, optional) -- disables further events after this one has been triggered; defaults to false
• immediately (boolean, optional) -- fail immediately; defaults to false

Describes a single state-change event for blkdebug.

Members

• event (BlkdebugEvent) -- trigger event
• state (int, optional) -- the current state identifier blkdebug needs to be in; defaults to "any"
• new_state (int) -- the state identifier blkdebug is supposed to assume if this event is triggered

Driver specific block device options for blkdebug.

Members

• image (BlockdevRef) -- underlying raw block device (or image file)
• config (string, optional) -- filename of the configuration file
• align (int, optional) -- required alignment for requests in bytes, must be positive power of 2, or 0 for default
• max-transfer (int, optional) -- maximum size for I/O transfers in bytes, must be positive multiple of align and of the underlying file's request alignment (but need not be a power of 2), or 0 for default (since 2.10)
• opt-write-zero (int, optional) -- preferred alignment for write zero requests in bytes, must be positive multiple of align and of the underlying file's request alignment (but need not be a power of 2), or 0 for default (since 2.10)
• max-write-zero (int, optional) -- maximum size for write zero requests in bytes, must be positive multiple of align, of opt-write-zero, and of the underlying file's request alignment (but need not be a power of 2), or 0 for default (since 2.10)
• opt-discard (int, optional) -- preferred alignment for discard requests in bytes, must be positive multiple of align and of the underlying file's request alignment (but need not be a power of 2), or 0 for default (since 2.10)
• max-discard (int, optional) -- maximum size for discard requests in bytes, must be positive multiple of align, of opt-discard, and of the underlying file's request alignment (but need not be a power of 2), or 0 for default (since 2.10)
• inject-error ([BlkdebugInjectErrorOptions], optional) -- array of error injection descriptions
• set-state ([BlkdebugSetStateOptions], optional) -- array of state-change descriptions
• take-child-perms ([BlockPermission], optional) -- Permissions to take on image in addition to what is necessary anyway (which depends on how the blkdebug node is used).  Defaults to none.  (since 5.0)
• unshare-child-perms ([BlockPermission], optional) -- Permissions not to share on image in addition to what cannot be shared anyway (which depends on how the blkdebug node is used).  Defaults to none.  (since 5.0)

Driver specific block device options for blklogwrites.

Members

• file (BlockdevRef) -- block device
• log (BlockdevRef) -- block device used to log writes to file
• log-sector-size (int, optional) -- sector size used in logging writes to file, determines granularity of offsets and sizes of writes (default: 512)
• log-append (boolean, optional) -- append to an existing log (default: false)
• log-super-update-interval (int, optional) -- interval of write requests after which the log super block is updated to disk (default: 4096)

Driver specific block device options for blkverify.

Members

• test (BlockdevRef) -- block device to be tested
• raw (BlockdevRef) -- raw image used for verification

Driver specific block device options for blkreplay.

Members

• image (BlockdevRef) -- disk image which should be controlled with blkreplay

An enumeration of quorum read patterns.

Values

• quorum -- read all the children and do a quorum vote on reads
• fifo -- read only from the first child that has not failed

Driver specific block device options for Quorum

Members

• blkverify (boolean, optional) -- true if the driver must print content mismatch set to false by default
• children ([BlockdevRef]) -- the children block devices to use
• vote-threshold (int) -- the vote limit under which a read will fail
• rewrite-corrupted (boolean, optional) -- rewrite corrupted data when quorum is reached (Since 2.1)
• read-pattern (QuorumReadPattern, optional) -- choose read pattern and set to quorum by default (Since 2.2)

Driver specific block device options for Gluster

Members

• volume (string) -- name of gluster volume where VM image resides
• path (string) -- absolute path to image file in gluster volume
• server ([SocketAddress]) -- gluster servers description
• debug (int, optional) -- libgfapi log level (default '4' which is Error) (Since 2.8)
• logfile (string, optional) -- libgfapi log file (default /dev/stderr) (Since 2.8)

Availability: CONFIG_BLKIO

Driver specific block device options for the io_uring backend.

Members

• filename (string) -- path to the image file

Availability: CONFIG_BLKIO

Driver specific block device options for the nvme-io_uring backend.

Members

• path (string) -- path to the NVMe namespace's character device (e.g. /dev/ng0n1).

Availability: CONFIG_BLKIO

Driver specific block device options for the virtio-blk-vfio-pci backend.

Members

• path (string) -- path to the PCI device's sysfs directory (e.g. /sys/bus/pci/devices/0000:00:01.0).

Availability: CONFIG_BLKIO

Driver specific block device options for the virtio-blk-vhost-user backend.

Members

• path (string) -- path to the vhost-user UNIX domain socket.

Availability: CONFIG_BLKIO

Driver specific block device options for the virtio-blk-vhost-vdpa backend.

Members

• path (string) -- path to the vhost-vdpa character device.

Features

• fdset -- Member path supports the special "/dev/fdset/N" path (since 8.1)

An enumeration of libiscsi transport types

Values

• tcp -- Not documented
• iser -- Not documented

An enumeration of header digests supported by libiscsi

Values

• crc32c -- Not documented
• none -- Not documented
• crc32c-none -- Not documented
• none-crc32c -- Not documented

Driver specific block device options for iscsi

Members

• transport (IscsiTransport) -- The iscsi transport type
• portal (string) -- The address of the iscsi portal
• target (string) -- The target iqn name
• lun (int, optional) -- LUN to connect to.  Defaults to 0.
• user (string, optional) -- User name to log in with.  If omitted, no CHAP authentication is performed.
• password-secret (string, optional) -- The ID of a QCryptoSecret object providing the password for the login.  This option is required if user is specified.
• initiator-name (string, optional) -- The iqn name we want to identify to the target as. If this option is not specified, an initiator name is generated automatically.
• header-digest (IscsiHeaderDigest, optional) -- The desired header digest.  Defaults to none-crc32c.
• timeout (int, optional) -- Timeout in seconds after which a request will timeout.  0 means no timeout and is the default.

Values

• cephx -- Not documented
• none -- Not documented

Values

• luks-any -- Used for opening either luks or luks2 (Since 8.0)
• luks -- Not documented
• luks2 -- Not documented

Members

• key-secret (string) -- ID of a QCryptoSecret object providing a passphrase for unlocking the encryption

Members

• cipher-alg (QCryptoCipherAlgo, optional) -- The encryption algorithm
• The members of RbdEncryptionOptionsLUKSBase.

Members

• The members of RbdEncryptionOptionsLUKSBase.

Members

• The members of RbdEncryptionOptionsLUKSBase.

Members

• The members of RbdEncryptionOptionsLUKSBase.

Members

• The members of RbdEncryptionCreateOptionsLUKSBase.

Members

• The members of RbdEncryptionCreateOptionsLUKSBase.

Members

• format (RbdImageEncryptionFormat) -- Encryption format.
• parent (RbdEncryptionOptions, optional) -- Parent image encryption options (for cloned images).  Can be left unspecified if this cloned image is encrypted using the same format and secret as its parent image (i.e. not explicitly formatted) or if its parent image is not encrypted.  (Since 8.0)
• When format is luks: The members of RbdEncryptionOptionsLUKS.
• When format is luks2: The members of RbdEncryptionOptionsLUKS2.
• When format is luks-any: The members of RbdEncryptionOptionsLUKSAny.

Members

• format (RbdImageEncryptionFormat) -- Encryption format.
• When format is luks: The members of RbdEncryptionCreateOptionsLUKS.
• When format is luks2: The members of RbdEncryptionCreateOptionsLUKS2.

Members

• pool (string) -- Ceph pool name.
• namespace (string, optional) -- Rados namespace name in the Ceph pool.  (Since 5.0)
• image (string) -- Image name in the Ceph pool.
• conf (string, optional) -- path to Ceph configuration file.  Values in the configuration file will be overridden by options specified via QAPI.
• snapshot (string, optional) -- Ceph snapshot name.
• encrypt (RbdEncryptionOptions, optional) -- Image encryption options.  (Since 6.1)
• user (string, optional) -- Ceph id name.
• auth-client-required ([RbdAuthMode], optional) -- Acceptable authentication modes.  This maps to Ceph configuration option "auth_client_required".  (Since 3.0)
• key-secret (string, optional) -- ID of a QCryptoSecret object providing a key for cephx authentication.  This maps to Ceph configuration option "key". (Since 3.0)
• server ([InetSocketAddressBase], optional) -- Monitor host address and port.  This maps to the "mon_host" Ceph option.

Availability: CONFIG_REPLICATION

An enumeration of replication modes.

Values

• primary -- Primary mode, the vm's state will be sent to secondary QEMU.
• secondary -- Secondary mode, receive the vm's state from primary QEMU.

Availability: CONFIG_REPLICATION

Driver specific block device options for replication

Members

• mode (ReplicationMode) -- the replication mode
• top-id (string, optional) -- In secondary mode, node name or device ID of the root node who owns the replication node chain.  Must not be given in primary mode.
• The members of BlockdevOptionsGenericFormat.

An enumeration of NFS transport types

Values

• inet -- TCP transport

Captures the address of the socket

Members

• type (NFSTransport) -- transport type used for NFS (only TCP supported)
• host (string) -- host address for NFS server

Driver specific block device option for NFS

Members

• server (NFSServer) -- host address
• path (string) -- path of the image on the host
• user (int, optional) -- UID value to use when talking to the server (defaults to 65534 on Windows and getuid() on unix)
• group (int, optional) -- GID value to use when talking to the server (defaults to 65534 on Windows and getgid() in unix)
• tcp-syn-count (int, optional) -- number of SYNs during the session establishment (defaults to libnfs default)
• readahead-size (int, optional) -- set the readahead size in bytes (defaults to libnfs default)
• page-cache-size (int, optional) -- set the pagecache size in bytes (defaults to libnfs default)
• debug (int, optional) -- set the NFS debug level (max 2) (defaults to libnfs default)

Driver specific block device options shared by all protocols supported by the curl backend.

Members

• url (string) -- URL of the image file
• readahead (int, optional) -- Size of the read-ahead cache; must be a multiple of 512 (defaults to 256 kB)
• timeout (int, optional) -- Timeout for connections, in seconds (defaults to 5)
• username (string, optional) -- Username for authentication (defaults to none)
• password-secret (string, optional) -- ID of a QCryptoSecret object providing a password for authentication (defaults to no password)
• proxy-username (string, optional) -- Username for proxy authentication (defaults to none)
• proxy-password-secret (string, optional) -- ID of a QCryptoSecret object providing a password for proxy authentication (defaults to no password)

Driver specific block device options for HTTP connections over the curl backend.  URLs must start with "http://".

Members

• cookie (string, optional) -- List of cookies to set; format is "name1=content1; name2=content2;" as explained by CURLOPT_COOKIE(3).  Defaults to no cookies.
• cookie-secret (string, optional) -- ID of a QCryptoSecret object providing the cookie data in a secure way.  See cookie for the format.  (since 2.10)
• The members of BlockdevOptionsCurlBase.

Driver specific block device options for HTTPS connections over the curl backend.  URLs must start with "https://".

Members

• cookie (string, optional) -- List of cookies to set; format is "name1=content1; name2=content2;" as explained by CURLOPT_COOKIE(3).  Defaults to no cookies.
• sslverify (boolean, optional) -- Whether to verify the SSL certificate's validity (defaults to true)
• cookie-secret (string, optional) -- ID of a QCryptoSecret object providing the cookie data in a secure way.  See cookie for the format.  (since 2.10)
• The members of BlockdevOptionsCurlBase.

Driver specific block device options for FTP connections over the curl backend.  URLs must start with "ftp://".

Members

• The members of BlockdevOptionsCurlBase.

Driver specific block device options for FTPS connections over the curl backend.  URLs must start with "ftps://".

Members

• sslverify (boolean, optional) -- Whether to verify the SSL certificate's validity (defaults to true)
• The members of BlockdevOptionsCurlBase.

Driver specific block device options for NBD.

Members

• server (SocketAddress) -- NBD server address
• export (string, optional) -- export name
• tls-creds (string, optional) -- TLS credentials ID
• tls-hostname (string, optional) -- TLS hostname override for certificate validation (Since 7.0)
• x-dirty-bitmap (string, optional) -- A metadata context name such as "qemu:dirty-bitmap:NAME" or "qemu:allocation-depth" to query in place of the traditional "base:allocation" block status (see NBD_OPT_LIST_META_CONTEXT in the NBD protocol; and yes, naming this option x-context would have made more sense) (since 3.0)
• reconnect-delay (int, optional) -- On an unexpected disconnect, the nbd client tries to connect again until succeeding or encountering a serious error.  During the first reconnect-delay seconds, all requests are paused and will be rerun on a successful reconnect.  After that time, any delayed requests and all future requests before a successful reconnect will immediately fail.  Default 0 (Since 4.2)
• open-timeout (int, optional) -- In seconds.  If zero, the nbd driver tries the connection only once, and fails to open if the connection fails. If non-zero, the nbd driver will repeat connection attempts until successful or until open-timeout seconds have elapsed. Default 0 (Since 7.0)

Features

• unstable -- Member x-dirty-bitmap is experimental.

Driver specific block device options for the raw driver.

Members

• offset (int, optional) -- position where the block device starts
• size (int, optional) -- the assumed size of the device
• The members of BlockdevOptionsGenericFormat.

Driver specific block device options for the throttle driver

Members

• throttle-group (string) -- the name of the throttle-group object to use.  It must already exist.
• file (BlockdevRef) -- reference to or definition of the data source block device

Driver specific block device options for the copy-on-read driver.

Members

• bottom (string, optional) -- The name of a non-filter node (allocation-bearing layer) that limits the COR operations in the backing chain (inclusive), so that no data below this node will be copied by this filter. If option is absent, the limit is not applied, so that data from all backing layers may be copied.
• The members of BlockdevOptionsGenericFormat.

An enumeration of possible behaviors for copy-before-write operation failures.

Values

• break-guest-write -- report the error to the guest.  This way, the guest will not be able to overwrite areas that cannot be backed up, so the backup process remains valid.
• break-snapshot -- continue guest write.  Doing so will make the provided snapshot state invalid and any backup or export process based on it will finally fail.

Driver specific block device options for the copy-before-write driver, which does so called copy-before-write operations: when data is written to the filter, the filter first reads corresponding blocks from its file child and copies them to target child.  After successfully copying, the write request is propagated to file child. If copying fails, the original write request is failed too and no data is written to file child.

Members

• target (BlockdevRef) -- The target for copy-before-write operations.
• bitmap (BlockDirtyBitmap, optional) -- If specified, copy-before-write filter will do copy-before-write operations only for dirty regions of the bitmap.  Bitmap size must be equal to length of file and target child of the filter.  Note also, that bitmap is used only to initialize internal bitmap of the process, so further modifications (or removing) of specified bitmap doesn't influence the filter.  (Since 7.0)
• on-cbw-error (OnCbwError, optional) -- Behavior on failure of copy-before-write operation. Default is break-guest-write.  (Since 7.1)
• cbw-timeout (int, optional) -- Zero means no limit.  Non-zero sets the timeout in seconds for copy-before-write operation.  When a timeout occurs, the respective copy-before-write operation will fail, and the on-cbw-error parameter will decide how this failure is handled. Default 0.  (Since 7.1)
• min-cluster-size (int, optional) -- Minimum size of blocks used by copy-before-write operations.  Has to be a power of 2.  No effect if smaller than the maximum of the target's cluster size and 64 KiB.  Default 0. (Since 9.2)
• The members of BlockdevOptionsGenericFormat.

Options for creating a block device.  Many options are available for all block devices, independent of the block driver:

Members

• driver (BlockdevDriver) -- block driver name
• node-name (string, optional) -- the node name of the new node (Since 2.0).  This option is required on the top level of blockdev-add.  Valid node names start with an alphabetic character and may contain only alphanumeric characters, '-', '.' and '_'.  Their maximum length is 31 characters.
• discard (BlockdevDiscardOptions, optional) -- discard-related options (default: ignore)
• cache (BlockdevCacheOptions, optional) -- cache-related options
• active (boolean, optional) -- whether the block node should be activated (default: true). Having inactive block nodes is useful primarily for migration because it allows opening an image on the destination while the source is still holding locks for it. (Since 10.0)
• read-only (boolean, optional) -- whether the block device should be read-only (default: false).  Note that some block drivers support only read-only access, either generally or in certain configurations.  In this case, the default value does not work and the option must be specified explicitly.
• auto-read-only (boolean, optional) -- if true and read-only is false, QEMU may automatically decide not to open the image read-write as requested, but fall back to read-only instead (and switch between the modes later), e.g. depending on whether the image file is writable or whether a writing user is attached to the node (default: false, since 3.1)
• detect-zeroes (BlockdevDetectZeroesOptions, optional) -- detect and optimize zero writes (Since 2.1) (default: off)
• force-share (boolean, optional) -- force share all permission on added nodes.  Requires read-only=true.  (Since 2.10)
• When driver is blkdebug: The members of BlockdevOptionsBlkdebug.
• When driver is blklogwrites: The members of BlockdevOptionsBlklogwrites.
• When driver is blkverify: The members of BlockdevOptionsBlkverify.
• When driver is blkreplay: The members of BlockdevOptionsBlkreplay.
• When driver is bochs: The members of BlockdevOptionsGenericFormat.
• When driver is cloop: The members of BlockdevOptionsGenericFormat.
• When driver is compress: The members of BlockdevOptionsGenericFormat.
• When driver is copy-before-write: The members of BlockdevOptionsCbw.
• When driver is copy-on-read: The members of BlockdevOptionsCor.
• When driver is dmg: The members of BlockdevOptionsGenericFormat.
• When driver is file: The members of BlockdevOptionsFile.
• When driver is ftp: The members of BlockdevOptionsCurlFtp.
• When driver is ftps: The members of BlockdevOptionsCurlFtps.
• When driver is gluster: The members of BlockdevOptionsGluster.
• When driver is host_cdrom: The members of BlockdevOptionsFile.
• When driver is host_device: The members of BlockdevOptionsFile.
• When driver is http: The members of BlockdevOptionsCurlHttp.
• When driver is https: The members of BlockdevOptionsCurlHttps.
• When driver is io_uring: The members of BlockdevOptionsIoUring.
• When driver is iscsi: The members of BlockdevOptionsIscsi.
• When driver is luks: The members of BlockdevOptionsLUKS.
• When driver is nbd: The members of BlockdevOptionsNbd.
• When driver is nfs: The members of BlockdevOptionsNfs.
• When driver is null-aio: The members of BlockdevOptionsNull.
• When driver is null-co: The members of BlockdevOptionsNull.
• When driver is nvme: The members of BlockdevOptionsNVMe.
• When driver is nvme-io_uring: The members of BlockdevOptionsNvmeIoUring.
• When driver is parallels: The members of BlockdevOptionsGenericFormat.
• When driver is preallocate: The members of BlockdevOptionsPreallocate.
• When driver is qcow2: The members of BlockdevOptionsQcow2.
• When driver is qcow: The members of BlockdevOptionsQcow.
• When driver is qed: The members of BlockdevOptionsGenericCOWFormat.
• When driver is quorum: The members of BlockdevOptionsQuorum.
• When driver is raw: The members of BlockdevOptionsRaw.
• When driver is rbd: The members of BlockdevOptionsRbd.
• When driver is replication: The members of BlockdevOptionsReplication.
• When driver is snapshot-access: The members of BlockdevOptionsGenericFormat.
• When driver is ssh: The members of BlockdevOptionsSsh.
• When driver is throttle: The members of BlockdevOptionsThrottle.
• When driver is vdi: The members of BlockdevOptionsGenericFormat.
• When driver is vhdx: The members of BlockdevOptionsGenericFormat.
• When driver is virtio-blk-vfio-pci: The members of BlockdevOptionsVirtioBlkVfioPci.
• When driver is virtio-blk-vhost-user: The members of BlockdevOptionsVirtioBlkVhostUser.
• When driver is virtio-blk-vhost-vdpa: The members of BlockdevOptionsVirtioBlkVhostVdpa.
• When driver is vmdk: The members of BlockdevOptionsGenericCOWFormat.
• When driver is vpc: The members of BlockdevOptionsGenericFormat.
• When driver is vvfat: The members of BlockdevOptionsVVFAT.

Reference to a block device.

Alternatives

• definition (BlockdevOptions) -- defines a new block device inline
• reference (string) -- references the ID of an existing block device

Reference to a block device.

Alternatives

• definition (BlockdevOptions) -- defines a new block device inline
• reference (string) -- references the ID of an existing block device.  An empty string means that no block device should be referenced. Deprecated; use null instead.
• null (null) -- No block device should be referenced (since 2.10)

Creates a new block device.

Arguments

• The members of BlockdevOptions.

Reopens one or more block devices using the given set of options. Any option not specified will be reset to its default value regardless of its previous status.  If an option cannot be changed or a particular driver does not support reopening then the command will return an error.  All devices in the list are reopened in one transaction, so if one of them fails then the whole transaction is cancelled.

The command receives a list of block devices to reopen.  For each one of them, the top-level node-name option (from BlockdevOptions) must be specified and is used to select the block device to be reopened.  Other node-name options must be either omitted or set to the current name of the appropriate node.  This command won't change any node name and any attempt to do it will result in an error.

In the case of options that refer to child nodes, the behavior of this command depends on the value:

1. A set of options (BlockdevOptions): the child is reopened with the specified set of options.
2. A reference to the current child: the child is reopened using its existing set of options.
3. A reference to a different node: the current child is replaced with the specified one.
4. NULL: the current child (if any) is detached.

Options (1) and (2) are supported in all cases.  Option (3) is supported for file and backing, and option (4) for backing only.

Unlike with blockdev-add, the backing option must always be present unless the node being reopened does not have a backing file and its image does not have a default backing file name as part of its metadata.

Arguments

• options ([BlockdevOptions]) -- Not documented

Deletes a block device that has been added using blockdev-add.  The command will fail if the node is attached to a device or is otherwise being used.

Arguments

• node-name (string) -- Name of the graph node to delete.

Example:

-> { "execute": "blockdev-add",
     "arguments": {
          "driver": "qcow2",
          "node-name": "node0",
          "file": {
              "driver": "file",
              "filename": "test.qcow2"
          }
     }
   }
<- { "return": {} }

-> { "execute": "blockdev-del",
     "arguments": { "node-name": "node0" }
   }
<- { "return": {} }

Activate or inactivate a block device. Use this to manage the handover of block devices on migration with qemu-storage-daemon.

Activating a node automatically activates all of its child nodes first. Inactivating a node automatically inactivates any of its child nodes that are not in use by a still active node.

Arguments

• node-name (string, optional) -- Name of the graph node to activate or inactivate. By default, all nodes are affected by the operation.
• active (boolean) -- true if the nodes should be active when the command returns success, false if they should be inactive.

Example:

-> { "execute": "blockdev-set-active",
     "arguments": {
          "node-name": "node0",
          "active": false
     }
   }
<- { "return": {} }

Driver specific image creation options for file.

Members

• filename (string) -- Filename for the new image file
• size (int) -- Size of the virtual disk in bytes
• preallocation (PreallocMode, optional) -- Preallocation mode for the new image (default: off; allowed values: off, falloc (if CONFIG_POSIX_FALLOCATE), full (if CONFIG_POSIX))
• nocow (boolean, optional) -- Turn off copy-on-write (valid only on btrfs; default: off)
• extent-size-hint (int, optional) -- Extent size hint to add to the image file; 0 for not adding an extent size hint (default: 1 MB, since 5.1)

Driver specific image creation options for gluster.

Members

• location (BlockdevOptionsGluster) -- Where to store the new image file
• size (int) -- Size of the virtual disk in bytes
• preallocation (PreallocMode, optional) -- Preallocation mode for the new image (default: off; allowed values: off, falloc (if CONFIG_GLUSTERFS_FALLOCATE), full (if CONFIG_GLUSTERFS_ZEROFILL))

Driver specific image creation options for LUKS.

Members

• file (BlockdevRef, optional) -- Node to create the image format on, mandatory except when 'preallocation' is not requested
• header (BlockdevRef, optional) -- Block device holding a detached LUKS header.  (since 9.0)
• size (int) -- Size of the virtual disk in bytes
• preallocation (PreallocMode, optional) -- Preallocation mode for the new image (since: 4.2) (default: off; allowed values: off, metadata, falloc, full)
• The members of QCryptoBlockCreateOptionsLUKS.

Driver specific image creation options for NFS.

Members

• location (BlockdevOptionsNfs) -- Where to store the new image file
• size (int) -- Size of the virtual disk in bytes

Driver specific image creation options for parallels.

Members

• file (BlockdevRef) -- Node to create the image format on
• size (int) -- Size of the virtual disk in bytes
• cluster-size (int, optional) -- Cluster size in bytes (default: 1 MB)

Driver specific image creation options for qcow.

Members

• file (BlockdevRef) -- Node to create the image format on
• size (int) -- Size of the virtual disk in bytes
• backing-file (string, optional) -- File name of the backing file if a backing file should be used
• encrypt (QCryptoBlockCreateOptions, optional) -- Encryption options if the image should be encrypted

Values

• v2 -- The original QCOW2 format as introduced in qemu 0.10 (version 2)
• v3 -- The extended QCOW2 format as introduced in qemu 1.1 (version 3)

Compression type used in qcow2 image file

Values

• zlib -- zlib compression, see <http://zlib.net/>
• zstd -- zstd compression, see <http://github.com/facebook/zstd>

Driver specific image creation options for qcow2.

Members

• file (BlockdevRef) -- Node to create the image format on
• data-file (BlockdevRef, optional) -- Node to use as an external data file in which all guest data is stored so that only metadata remains in the qcow2 file (since: 4.0)
• data-file-raw (boolean, optional) -- True if the external data file must stay valid as a standalone (read-only) raw image without looking at qcow2 metadata (default: false; since: 4.0)
• extended-l2 (boolean, optional) -- True to make the image have extended L2 entries (default: false; since 5.2)
• size (int) -- Size of the virtual disk in bytes
• version (BlockdevQcow2Version, optional) -- Compatibility level (default: v3)
• backing-file (string, optional) -- File name of the backing file if a backing file should be used
• backing-fmt (BlockdevDriver, optional) -- Name of the block driver to use for the backing file
• encrypt (QCryptoBlockCreateOptions, optional) -- Encryption options if the image should be encrypted
• cluster-size (int, optional) -- qcow2 cluster size in bytes (default: 65536)
• preallocation (PreallocMode, optional) -- Preallocation mode for the new image (default: off; allowed values: off, falloc, full, metadata)
• lazy-refcounts (boolean, optional) -- True if refcounts may be updated lazily (default: off)
• refcount-bits (int, optional) -- Width of reference counts in bits (default: 16)
• compression-type (Qcow2CompressionType, optional) -- The image cluster compression method (default: zlib, since 5.1)

Driver specific image creation options for qed.

Members

• file (BlockdevRef) -- Node to create the image format on
• size (int) -- Size of the virtual disk in bytes
• backing-file (string, optional) -- File name of the backing file if a backing file should be used
• backing-fmt (BlockdevDriver, optional) -- Name of the block driver to use for the backing file
• cluster-size (int, optional) -- Cluster size in bytes (default: 65536)
• table-size (int, optional) -- L1/L2 table size (in clusters)

Driver specific image creation options for rbd/Ceph.

Members

• location (BlockdevOptionsRbd) -- Where to store the new image file.  This location cannot point to a snapshot.
• size (int) -- Size of the virtual disk in bytes
• cluster-size (int, optional) -- RBD object size
• encrypt (RbdEncryptionCreateOptions, optional) -- Image encryption options.  (Since 6.1)

Subformat options for VMDK images

Values

• monolithicSparse -- Single file image with sparse cluster allocation
• monolithicFlat -- Single flat data image and a descriptor file
• twoGbMaxExtentSparse -- Data is split into 2GB (per virtual LBA) sparse extent files, in addition to a descriptor file
• twoGbMaxExtentFlat -- Data is split into 2GB (per virtual LBA) flat extent files, in addition to a descriptor file
• streamOptimized -- Single file image sparse cluster allocation, optimized for streaming over network.

Adapter type info for VMDK images

Values

• ide -- Not documented
• buslogic -- Not documented
• lsilogic -- Not documented
• legacyESX -- Not documented

Driver specific image creation options for VMDK.

Members

• file (BlockdevRef) -- Where to store the new image file.  This refers to the image file for monolithcSparse and streamOptimized format, or the descriptor file for other formats.
• size (int) -- Size of the virtual disk in bytes
• extents ([BlockdevRef], optional) -- Where to store the data extents.  Required for monolithcFlat, twoGbMaxExtentSparse and twoGbMaxExtentFlat formats.  For monolithicFlat, only one entry is required; for twoGbMaxExtent* formats, the number of entries required is calculated as extent_number = virtual_size / 2GB.  Providing more extents than will be used is an error.
• subformat (BlockdevVmdkSubformat, optional) -- The subformat of the VMDK image.  Default: "monolithicSparse".
• backing-file (string, optional) -- The path of backing file.  Default: no backing file is used.
• adapter-type (BlockdevVmdkAdapterType, optional) -- The adapter type used to fill in the descriptor. Default: ide.
• hwversion (string, optional) -- Hardware version.  The meaningful options are "4" or "6".  Default: "4".
• toolsversion (string, optional) -- VMware guest tools version.  Default: "2147483647" (Since 6.2)
• zeroed-grain (boolean, optional) -- Whether to enable zeroed-grain feature for sparse subformats.  Default: false.

Driver specific image creation options for SSH.

Members

• location (BlockdevOptionsSsh) -- Where to store the new image file
• size (int) -- Size of the virtual disk in bytes

Driver specific image creation options for VDI.

Members

• file (BlockdevRef) -- Node to create the image format on
• size (int) -- Size of the virtual disk in bytes
• preallocation (PreallocMode, optional) -- Preallocation mode for the new image (default: off; allowed values: off, metadata)

Values

• dynamic -- Growing image file
• fixed -- Preallocated fixed-size image file

Driver specific image creation options for vhdx.

Members

• file (BlockdevRef) -- Node to create the image format on
• size (int) -- Size of the virtual disk in bytes
• log-size (int, optional) -- Log size in bytes, must be a multiple of 1 MB (default: 1 MB)
• block-size (int, optional) -- Block size in bytes, must be a multiple of 1 MB and not larger than 256 MB (default: automatically choose a block size depending on the image size)
• subformat (BlockdevVhdxSubformat, optional) -- vhdx subformat (default: dynamic)
• block-state-zero (boolean, optional) -- Force use of payload blocks of type 'ZERO'. Non-standard, but default.  Do not set to 'off' when using 'qemu-img convert' with subformat=dynamic.

Values

• dynamic -- Growing image file
• fixed -- Preallocated fixed-size image file

Driver specific image creation options for vpc (VHD).

Members

• file (BlockdevRef) -- Node to create the image format on
• size (int) -- Size of the virtual disk in bytes
• subformat (BlockdevVpcSubformat, optional) -- vhdx subformat (default: dynamic)
• force-size (boolean, optional) -- Force use of the exact byte size instead of rounding to the next size that can be represented in CHS geometry (default: false)

Options for creating an image format on a given node.

Members

• driver (BlockdevDriver) -- block driver to create the image format
• When driver is file: The members of BlockdevCreateOptionsFile.
• When driver is gluster: The members of BlockdevCreateOptionsGluster.
• When driver is luks: The members of BlockdevCreateOptionsLUKS.
• When driver is nfs: The members of BlockdevCreateOptionsNfs.
• When driver is parallels: The members of BlockdevCreateOptionsParallels.
• When driver is qcow: The members of BlockdevCreateOptionsQcow.
• When driver is qcow2: The members of BlockdevCreateOptionsQcow2.
• When driver is qed: The members of BlockdevCreateOptionsQed.
• When driver is rbd: The members of BlockdevCreateOptionsRbd.
• When driver is ssh: The members of BlockdevCreateOptionsSsh.
• When driver is vdi: The members of BlockdevCreateOptionsVdi.
• When driver is vhdx: The members of BlockdevCreateOptionsVhdx.
• When driver is vmdk: The members of BlockdevCreateOptionsVmdk.
• When driver is vpc: The members of BlockdevCreateOptionsVpc.

Starts a job to create an image format on a given node.  The job is automatically finalized, but a manual job-dismiss is required.

Arguments

• job-id (string) -- Identifier for the newly created job.
• options (BlockdevCreateOptions) -- Options for the image creation.

Driver specific image amend options for LUKS.

Members

• The members of QCryptoBlockAmendOptionsLUKS.

Driver specific image amend options for qcow2.  For now, only encryption options can be amended

Members

• encrypt (QCryptoBlockAmendOptions, optional) -- Encryption options to be amended

Options for amending an image format

Members

• driver (BlockdevDriver) -- Block driver of the node to amend.
• When driver is luks: The members of BlockdevAmendOptionsLUKS.
• When driver is qcow2: The members of BlockdevAmendOptionsQcow2.

This command is unstable/experimental.

Starts a job to amend format specific options of an existing open block device The job is automatically finalized, but a manual job-dismiss is required.

Arguments

• job-id (string) -- Identifier for the newly created job.
• node-name (string) -- Name of the block node to work on
• options (BlockdevAmendOptions) -- Options (driver specific)
• force (boolean, optional) -- Allow unsafe operations, format specific For luks that allows erase of the last active keyslot (permanent loss of data), and replacement of an active keyslot (possible loss of data if IO error happens)

Features

• unstable -- This command is experimental.

An enumeration of action that has been taken when a DISK I/O occurs

Values

• ignore -- error has been ignored
• report -- error has been reported to the device
• stop -- error caused VM to be stopped

Emitted when a disk image is being marked corrupt.  The image can be identified by its device or node name.  The 'device' field is always present for compatibility reasons, but it can be empty ("") if the image does not have a device name associated.

Members

• device (string) -- device name.  This is always present for compatibility reasons, but it can be empty ("") if the image does not have a device name associated.
• node-name (string, optional) -- node name (Since: 2.4)
• msg (string) -- informative message for human consumption, such as the kind of corruption being detected.  It should not be parsed by machine as it is not guaranteed to be stable
• offset (int, optional) -- if the corruption resulted from an image access, this is the host's access offset into the image
• size (int, optional) -- if the corruption resulted from an image access, this is the access size
• fatal (boolean) -- if set, the image is marked corrupt and therefore unusable after this event and must be repaired (Since 2.2; before, every BLOCK_IMAGE_CORRUPTED event was fatal)

NOTE:

If action is "stop", a STOP event will eventually follow the BLOCK_IO_ERROR event.

Example:

<- { "event": "BLOCK_IMAGE_CORRUPTED",
     "data": { "device": "", "node-name": "drive", "fatal": false,
               "msg": "L2 table offset 0x2a2a2a00 unaligned (L1 index: 0)" },
     "timestamp": { "seconds": 1648243240, "microseconds": 906060 } }

Emitted when a disk I/O error occurs

Members

• qom-path (string) -- path to the device object in the QOM tree (since 9.2)
• device (string) -- device name.  This is always present for compatibility reasons, but it can be empty ("") if the image does not have a device name associated.
• node-name (string, optional) -- node name.  Note that errors may be reported for the root node that is directly attached to a guest device rather than for the node where the error occurred.  The node name is not present if the drive is empty.  (Since: 2.8)
• operation (IoOperationType) -- I/O operation
• action (BlockErrorAction) -- action that has been taken
• nospace (boolean, optional) -- true if I/O error was caused due to a no-space condition. This key is only present if query-block's io-status is present, please see query-block documentation for more information (since: 2.2)
• reason (string) -- human readable string describing the error cause.  (This field is a debugging aid for humans, it should not be parsed by applications) (since: 2.2)

NOTE:

If action is "stop", a STOP event will eventually follow the BLOCK_IO_ERROR event.

NOTE:

This event is rate-limited.

Example:

<- { "event": "BLOCK_IO_ERROR",
     "data": { "qom-path": "/machine/unattached/device[0]",
               "device": "ide0-hd1",
               "node-name": "#block212",
               "operation": "write",
               "action": "stop",
               "reason": "No space left on device" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Emitted when a block job has completed

Members

• type (JobType) -- job type
• device (string) -- The job identifier.  Originally the device name but other values are allowed since QEMU 2.7
• len (int) -- maximum progress value
• offset (int) -- current progress value.  On success this is equal to len. On failure this is less than len
• speed (int) -- rate limit, bytes per second
• error (string, optional) -- error message.  Only present on failure.  This field contains a human-readable error message.  There are no semantics other than that streaming has failed and clients should not try to interpret the error string

Example:

<- { "event": "BLOCK_JOB_COMPLETED",
     "data": { "type": "stream", "device": "virtio-disk0",
               "len": 10737418240, "offset": 10737418240,
               "speed": 0 },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }

Emitted when a block job has been cancelled

Members

• type (JobType) -- job type
• device (string) -- The job identifier.  Originally the device name but other values are allowed since QEMU 2.7
• len (int) -- maximum progress value
• offset (int) -- current progress value.  On success this is equal to len. On failure this is less than len
• speed (int) -- rate limit, bytes per second

Example:

<- { "event": "BLOCK_JOB_CANCELLED",
     "data": { "type": "stream", "device": "virtio-disk0",
               "len": 10737418240, "offset": 134217728,
               "speed": 0 },
     "timestamp": { "seconds": 1267061043, "microseconds": 959568 } }

Emitted when a block job encounters an error

Members

• device (string) -- The job identifier.  Originally the device name but other values are allowed since QEMU 2.7
• operation (IoOperationType) -- I/O operation
• action (BlockErrorAction) -- action that has been taken

Example:

<- { "event": "BLOCK_JOB_ERROR",
     "data": { "device": "ide0-hd1",
               "operation": "write",
               "action": "stop" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Emitted when a block job is ready to complete

Members

• type (JobType) -- job type
• device (string) -- The job identifier.  Originally the device name but other values are allowed since QEMU 2.7
• len (int) -- maximum progress value
• offset (int) -- current progress value.  On success this is equal to len. On failure this is less than len
• speed (int) -- rate limit, bytes per second

NOTE:

The "ready to complete" status is always reset by a BLOCK_JOB_ERROR event.

Example:

<- { "event": "BLOCK_JOB_READY",
     "data": { "device": "drive0", "type": "mirror", "speed": 0,
               "len": 2097152, "offset": 2097152 },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Emitted when a block job is awaiting explicit authorization to finalize graph changes via block-job-finalize.  If this job is part of a transaction, it will not emit this event until the transaction has converged first.

Members

• type (JobType) -- job type
• id (string) -- The job identifier.

Example:

<- { "event": "BLOCK_JOB_PENDING",
     "data": { "type": "mirror", "id": "backup_1" },
     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

Preallocation mode of QEMU image file

Values

• off -- no preallocation
• metadata -- preallocate only for metadata
• falloc -- like full preallocation but allocate disk space by posix_fallocate() rather than writing data.
• full -- preallocate all data by writing it to the device to ensure disk space is really available.  This data may or may not be zero, depending on the image format and storage.  full preallocation also sets up metadata correctly.

Emitted when writes on block device reaches or exceeds the configured write threshold.  For thin-provisioned devices, this means the device should be extended to avoid pausing for disk exhaustion.  The event is one shot.  Once triggered, it needs to be re-registered with another block-set-write-threshold command.

Members

• node-name (string) -- graph node name on which the threshold was exceeded.
• amount-exceeded (int) -- amount of data which exceeded the threshold, in bytes.
• write-threshold (int) -- last configured threshold, in bytes.

Change the write threshold for a block drive.  An event will be delivered if a write to this block drive crosses the configured threshold.  The threshold is an offset, thus must be non-negative. Default is no write threshold.  Setting the threshold to zero disables it.

This is useful to transparently resize thin-provisioned drives without the guest OS noticing.

Arguments

• node-name (string) -- graph node name on which the threshold must be set.
• write-threshold (int) -- configured threshold for the block device, bytes. Use 0 to disable the threshold.

Example:

-> { "execute": "block-set-write-threshold",
     "arguments": { "node-name": "mydev",
                    "write-threshold": 17179869184 } }
<- { "return": {} }

This command is unstable/experimental.

Dynamically reconfigure the block driver state graph.

Currently only supports adding and deleting quorum children.  A child will be added at the end of the list of children.  Its contents must be consistent with the other childrens' contents. Deleting a child that is not last in the list of children is problematic, because it "renumbers" the children following it.

Arguments

• parent (string) -- the id or name of the parent node.
• child (string, optional) -- the name of a child to be deleted.  Mutually exclusive with node.
• node (string, optional) -- the name of the node to be added.  Mutually exclusive with child.

Features

• unstable -- This command is experimental.

This command is unstable/experimental.

Move node and its children into the iothread.  If iothread is null then move node and its children into the main loop.

The node must not be attached to a BlockBackend.

Arguments

• node-name (string) -- the name of the block driver node
• iothread (StrOrNull) -- the name of the IOThread object or null for the main loop
• force (boolean, optional) -- true if the node and its children should be moved when a BlockBackend is already attached

Features

• unstable -- This command is experimental and intended for test cases that need control over IOThreads only.

An enumeration of the quorum operation types

Values

• read -- read operation
• write -- write operation
• flush -- flush operation

Emitted by the Quorum block driver if it fails to establish a quorum

Members

• reference (string) -- device name if defined else node name
• sector-num (int) -- number of the first sector of the failed read operation
• sectors-count (int) -- failed read operation sector count

NOTE:

This event is rate-limited.

Example:

<- { "event": "QUORUM_FAILURE",
     "data": { "reference": "usr1", "sector-num": 345435, "sectors-count": 5 },
     "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

Emitted to report a corruption of a Quorum file

Members

• type (QuorumOpType) -- quorum operation type (Since 2.6)
• error (string, optional) -- error message.  Only present on failure.  This field contains a human-readable error message.  There are no semantics other than that the block layer reported an error and clients should not try to interpret the error string.
• node-name (string) -- the graph node name of the block driver state
• sector-num (int) -- number of the first sector of the failed read operation
• sectors-count (int) -- failed read operation sector count

NOTE:

This event is rate-limited.

Example: Read operation

 <- { "event": "QUORUM_REPORT_BAD",
      "data": { "node-name": "node0", "sector-num": 345435, "sectors-count": 5,
                "type": "read" },
      "timestamp": { "seconds": 1344522075, "microseconds": 745528 } }

Example: Flush operation

 <- { "event": "QUORUM_REPORT_BAD",
      "data": { "node-name": "node0", "sector-num": 0, "sectors-count": 2097120,
                "type": "flush", "error": "Broken pipe" },
      "timestamp": { "seconds": 1456406829, "microseconds": 291763 } }

Members

• device (string) -- the device name or node-name of a root node to generate the snapshot from
• name (string) -- the name of the internal snapshot to be created

Synchronously take an internal snapshot of a block device, when the format of the image used supports it.  If the name is an empty string, or a snapshot with name already exists, the operation will fail.

Arguments

• The members of BlockdevSnapshotInternal.

Errors

• If device is not a valid block device, GenericError
• If any snapshot matching name exists, or name is empty, GenericError
• If the format of the image used does not support it, GenericError

NOTE:

Only some image formats such as qcow2 and rbd support internal snapshots.

Example:

-> { "execute": "blockdev-snapshot-internal-sync",
     "arguments": { "device": "ide-hd0",
                    "name": "snapshot0" }
   }
<- { "return": {} }

Synchronously delete an internal snapshot of a block device, when the format of the image used support it.  The snapshot is identified by name or id or both.  One of the name or id is required.  Return SnapshotInfo for the successfully deleted snapshot.

Arguments

• device (string) -- the device name or node-name of a root node to delete the snapshot from
• id (string, optional) -- optional the snapshot's ID to be deleted
• name (string, optional) -- optional the snapshot's name to be deleted

Return

SnapshotInfo -- SnapshotInfo

Errors

• If device is not a valid block device, GenericError
• If snapshot not found, GenericError
• If the format of the image used does not support it, GenericError
• If id and name are both not specified, GenericError

Example:

-> { "execute": "blockdev-snapshot-delete-internal-sync",
     "arguments": { "device": "ide-hd0",
                    "name": "snapshot0" }
   }
<- { "return": {
                   "id": "1",
                   "name": "snapshot0",
                   "vm-state-size": 0,
                   "date-sec": 1000012,
                   "date-nsec": 10,
                   "vm-clock-sec": 100,
                   "vm-clock-nsec": 20,
                   "icount": 220414
     }
   }

Not used by QMP; hack to let us use BlockGraphInfoList internally

Members

• unused-block-graph-info ([BlockGraphInfo]) -- Not documented

Members

• handshake-max-seconds (int, optional) -- Time limit, in seconds, at which a client that has not completed the negotiation handshake will be disconnected, or 0 for no limit (since 10.0; default: 10).
• tls-creds (string, optional) -- ID of the TLS credentials object (since 2.6).
• tls-authz (string, optional) -- ID of the QAuthZ authorization object used to validate the client's x509 distinguished name.  This object is is only resolved at time of use, so can be deleted and recreated on the fly while the NBD server is active.  If missing, it will default to denying access (since 4.0).
• max-connections (int, optional) -- The maximum number of connections to allow at the same time, 0 for unlimited.  Setting this to 1 also stops the server from advertising multiple client support (since 5.2; default: 100).

Keep this type consistent with the NbdServerOptionsLegacy type.  The only intended difference is using SocketAddress instead of SocketAddressLegacy.

Members

• addr (SocketAddress) -- Address on which to listen (since 4.2).
• The members of NbdServerOptionsBase.

Keep this type consistent with the NbdServerOptions type.  The only intended difference is using SocketAddressLegacy instead of SocketAddress.

Members

• addr (SocketAddressLegacy) -- Address on which to listen (since 1.3).
• The members of NbdServerOptionsBase.

Start an NBD server listening on the given host and port.  Block devices can then be exported using nbd-server-add.  The NBD server will present them as named exports; for example, another QEMU instance could refer to them as "nbd:HOST:PORT:exportname=NAME".

Arguments

• The members of NbdServerOptionsLegacy.

Errors

• if the server is already running

An NBD block export (common options shared between nbd-server-add and the NBD branch of block-export-add).

Members

• name (string, optional) -- Export name.  If unspecified, the device parameter is used as the export name.  (Since 2.12)
• description (string, optional) -- Free-form description of the export, up to 4096 bytes. (Since 5.0)

An NBD block export (distinct options used in the NBD branch of block-export-add).

Members

• bitmaps ([BlockDirtyBitmapOrStr], optional) -- Also export each of the named dirty bitmaps reachable from device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with the metadata context name "qemu:dirty-bitmap:BITMAP" to inspect each bitmap.  Since 7.1 bitmap may be specified by node/name pair.
• allocation-depth (boolean, optional) -- Also export the allocation depth map for device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with the metadata context name "qemu:allocation-depth" to inspect allocation details.  (since 5.2)
• The members of BlockExportOptionsNbdBase.

A vhost-user-blk block export.

Members

• addr (SocketAddress) -- The vhost-user socket on which to listen.  Both 'unix' and 'fd' SocketAddress types are supported.  Passed fds must be UNIX domain sockets.
• logical-block-size (int, optional) -- Logical block size in bytes.  Defaults to 512 bytes.
• num-queues (int, optional) -- Number of request virtqueues.  Must be greater than 0. Defaults to 1.

Possible allow_other modes for FUSE exports.

Values

• off -- Do not pass allow_other as a mount option.
• on -- Pass allow_other as a mount option.
• auto -- Try mounting with allow_other first, and if that fails, retry without allow_other.

Availability: CONFIG_FUSE

Options for exporting a block graph node on some (file) mountpoint as a raw image.

Members

• mountpoint (string) -- Path on which to export the block device via FUSE. This must point to an existing regular file.
• growable (boolean, optional) -- Whether writes beyond the EOF should grow the block node accordingly.  (default: false)
• allow-other (FuseExportAllowOther, optional) -- If this is off, only qemu's user is allowed access to this export.  That cannot be changed even with chmod or chown. Enabling this option will allow other users access to the export with the FUSE mount option "allow_other".  Note that using allow_other as a non-root user requires user_allow_other to be enabled in the global fuse.conf configuration file.  In auto mode (the default), the FUSE export driver will first attempt to mount the export with allow_other, and if that fails, try again without.  (since 6.1; default: auto)

A vduse-blk block export.

Members

• name (string) -- the name of VDUSE device (must be unique across the host).
• num-queues (int, optional) -- the number of virtqueues.  Defaults to 1.
• queue-size (int, optional) -- the size of virtqueue.  Defaults to 256.
• logical-block-size (int, optional) -- Logical block size in bytes.  Range [512, PAGE_SIZE] and must be power of 2.  Defaults to 512 bytes.
• serial (string, optional) -- the serial number of virtio block device.  Defaults to empty string.

An NBD block export, per legacy nbd-server-add command.

Members

• device (string) -- The device name or node name of the node to be exported
• writable (boolean, optional) -- Whether clients should be able to write to the device via the NBD connection (default false).
• bitmap (string, optional) -- Also export a single dirty bitmap reachable from device, so the NBD client can use NBD_OPT_SET_META_CONTEXT with the metadata context name "qemu:dirty-bitmap:BITMAP" to inspect the bitmap (since 4.0).
• The members of BlockExportOptionsNbdBase.

This command is deprecated.

Export a block node to QEMU's embedded NBD server.

The export name will be used as the id for the resulting block export.

Arguments

• The members of NbdServerAddOptions.

Features

• deprecated -- This command is deprecated.  Use block-export-add instead.

Errors

• if the server is not running
• if an export with the same name already exists

Mode for removing a block export.

Values

• safe -- Remove export if there are no existing connections, fail otherwise.
• hard -- Drop all connections immediately and remove export.

This command is deprecated.

Remove NBD export by name.

Arguments

• name (string) -- Block export id.
• mode (BlockExportRemoveMode, optional) -- Mode of command operation.  See BlockExportRemoveMode description.  Default is 'safe'.

Features

• deprecated -- This command is deprecated.  Use block-export-del instead.

Errors

• if the server is not running
• if export is not found
• if mode is 'safe' and there are existing connections

Stop QEMU's embedded NBD server, and unregister all devices previously added via nbd-server-add.

An enumeration of block export types

Values

• nbd -- NBD export
• vhost-user-blk -- vhost-user-blk export (since 5.2)
• fuse -- FUSE export (since: 6.0)
• vduse-blk -- vduse-blk export (since 7.1)

Describes a block export, i.e. how single node should be exported on an external interface.

Members

• type (BlockExportType) -- Block export type
• id (string) -- A unique identifier for the block export (across all export types)
• node-name (string) -- The node name of the block node to be exported (since: 5.2)
• writable (boolean, optional) -- True if clients should be able to write to the export (default false)
• writethrough (boolean, optional) -- If true, caches are flushed after every write request to the export before completion is signalled.  (since: 5.2; default: false)
• iothread (string, optional) -- The name of the iothread object where the export will run.  The default is to use the thread currently associated with the block node.  (since: 5.2)
• fixed-iothread (boolean, optional) -- True prevents the block node from being moved to another thread while the export is active.  If true and iothread is given, export creation fails if the block node cannot be moved to the iothread.  The default is false. (since: 5.2)
• allow-inactive (boolean, optional) -- If true, the export allows the exported node to be inactive. If it is created for an inactive block node, the node remains inactive. If the export type doesn't support running on an inactive node, an error is returned. If false, inactive block nodes are automatically activated before creating the export and trying to inactivate them later fails. (since: 10.0; default: false)
• When type is nbd: The members of BlockExportOptionsNbd.
• When type is vhost-user-blk: The members of BlockExportOptionsVhostUserBlk.
• When type is fuse: The members of BlockExportOptionsFuse.
• When type is vduse-blk: The members of BlockExportOptionsVduseBlk.

Creates a new block export.

Arguments

• The members of BlockExportOptions.

Request to remove a block export.  This drops the user's reference to the export, but the export may still stay around after this command returns until the shutdown of the export has completed.

Arguments

• id (string) -- Block export id.
• mode (BlockExportRemoveMode, optional) -- Mode of command operation.  See BlockExportRemoveMode description.  Default is 'safe'.

Errors

• if the export is not found
• if mode is 'safe' and the export is still in use (e.g. by existing client connections)

Emitted when a block export is removed and its id can be reused.

Members

• id (string) -- Block export id.

Information about a single block export.

Members

• id (string) -- The unique identifier for the block export
• type (BlockExportType) -- The block export type
• node-name (string) -- The node name of the block node that is exported
• shutting-down (boolean) -- True if the export is shutting down (e.g. after a block-export-del command, but before the shutdown has completed)

Return

[BlockExportInfo] -- A list of BlockExportInfo describing all block exports