pvscan man page

pvscan — List all physical volumes

Synopsis

pvscan option_args
   [ option_args ]
   [ position_args ]

Description

pvscan scans all supported LVM block devices in the system for PVs.

Scanning with lvmetad

pvscan operates differently when used with the lvmetad(8) daemon.

Scanning disks is required to read LVM metadata and identify LVM PVs. Once read, lvmetad caches the metadata so that LVM commands can read it without repeatedly scanning disks.  This is helpful because scanning disks is time consuming, and frequent scanning may interfere with the normal work of the system and disks.

When lvmetad is not used, LVM commands revert to scanning disks to read metadata.  Any LVM command that needs metadata will scan disks for it; running the pvscan command is not necessary for the sake of other LVM commands.

When lvmetad is used, LVM commands avoid scanning disks by reading metadata from lvmetad.  When new disks appear, they must be scanned so their metadata can be cached in lvmetad.  This is done by the command pvscan --cache, which scans disks and passes the metadata to lvmetad.

The pvscan --cache command is typically run automatically by system services when a new device appears.  Users do not generally need to run this command if the system and lvmetad are running properly.

Many scripts contain unnecessary pvscan (or vgscan) commands for historical reasons.  To avoid disrupting the system with extraneous disk scanning, an ordinary pvscan (without --cache) will simply read metadata from lvmetad like other LVM commands.  It does not do anything beyond displaying the current state of the cache.

Automatic activation

When event-driven system services detect a new LVM device, the first step is to automatically scan and cache the metadata from the device.  This is done by pvscan --cache.  A second step is to automatically activate LVs that are present on the new device.  This auto-activation is done by the same pvscan --cache command when the option '-a--activate ay' is included.

Auto-activation of VGs or LVs can be enabled/disabled using:
lvm.conf(5) activation/auto_activation_volume_list

For more information, see:
lvmconfig --withcomments activation/auto_activation_volume_list

When this setting is undefined, all LVs are auto-activated (when lvm is fully integrated with the event-driven system services.)

When a VG or LV is not auto-activated, traditional activation using vgchange or lvchange -a--activate is needed.

Usage

Display PV information.

pvscan

[ -e|--exported ]
[ -n|--novolumegroup ]
[ -s|--short ]
[ -u|--uuid ]
[ COMMON_OPTIONS ]

Populate the lvmetad cache by scanning PVs.

pvscan --cache

[ -b|--background ]
[ -a|--activate ay ]
[ -j|--major Number ]
[    --minor Number ]
[ COMMON_OPTIONS ]
[ String|PV ... ]

Common options for command:

[    --ignorelockingfailure ]
[    --reportformat basic|json ]

Common options for lvm:

[ -d|--debug ]
[ -h|--help ]
[ -q|--quiet ]
[ -t|--test ]
[ -v|--verbose ]
[ -y|--yes ]
[    --commandprofile String ]
[    --config String ]
[    --driverloaded y|n ]
[    --longhelp ]
[    --profile String ]
[    --version ]

Options

-a|--activate y|n|ay

Auto-activate LVs in a VG when the PVs scanned have completed the VG. (Only ay is applicable.)

-b|--background

If the operation requires polling, this option causes the command to return before the operation is complete, and polling is done in the background.

--cache

Scan one or more devices and send the metadata to lvmetad.

--commandprofile String

The command profile to use for command configuration. See lvm.conf(5) for more information about profiles.

--config String

Config settings for the command. These override lvm.conf settings. The String arg uses the same format as lvm.conf, or may use section/field syntax. See lvm.conf(5) for more information about config.

-d|--debug ...

Set debug level. Repeat from 1 to 6 times to increase the detail of messages sent to the log file and/or syslog (if configured).

--driverloaded y|n

If set to no, the command will not attempt to use device-mapper. For testing and debugging.

-e|--exported

Only show PVs belonging to exported VGs.

-h|--help

Display help text.

--ignorelockingfailure

Allows a command to continue with read-only metadata operations after locking failures.

--longhelp

Display long help text.

-j|--major Number

The major number of a device.

--minor Number

The minor number of a device.

-n|--novolumegroup

Only show PVs not belonging to any VG.

--profile String

An alias for --commandprofile or --metadataprofile, depending on the command.

-q|--quiet ...

Suppress output and log messages. Overrides --debug and --verbose. Repeat once to also suppress any prompts with answer 'no'.

--reportformat basic|json

Overrides current output format for reports which is defined globally by the report/output_format setting in lvm.conf. basic is the original format with columns and rows. If there is more than one report per command, each report is prefixed with the report name for identification. json produces report output in JSON format. See lvmreport(7) for more information.

-s|--short

Short listing format.

-t|--test

Run in test mode. Commands will not update metadata. This is implemented by disabling all metadata writing but nevertheless returning success to the calling function. This may lead to unusual error messages in multi-stage operations if a tool relies on reading back metadata it believes has changed but hasn't.

-u|--uuid

Show UUIDs in addition to device names.

-v|--verbose ...

Set verbose level. Repeat from 1 to 4 times to increase the detail of messages sent to stdout and stderr.

--version

Display version information.

-y|--yes

Do not prompt for confirmation interactively but always assume the answer yes. Use with extreme caution. (For automatic no, see -qq.)

Variables

PV
Physical Volume name, a device path under /dev. For commands managing physical extents, a PV positional arg generally accepts a suffix indicating a range (or multiple ranges) of physical extents (PEs). When the first PE is omitted, it defaults to the start of the device, and when the last PE is omitted it defaults to end. Start and end range (inclusive): PV[:PE-PE]... Start and length range (counting from 0): PV[:PE+PE]...

String
See the option description for information about the string content.

Size[UNIT]
Size is an input number that accepts an optional unit. Input units are always treated as base two values, regardless of capitalization, e.g. 'k' and 'K' both refer to 1024. The default input unit is specified by letter, followed by |UNIT. UNIT represents other possible input units: bBsSkKmMgGtTpPeE. b|B is bytes, s|S is sectors of 512 bytes, k|K is kilobytes, m|M is megabytes, g|G is gigabytes, t|T is terabytes, p|P is petabytes, e|E is exabytes. (This should not be confused with the output control --units, where capital letters mean multiple of 1000.)

Environment Variables

See lvm(8) for information about environment variables used by lvm. For example, LVM_VG_NAME can generally be substituted for a required VG parameter.

See Also

lvm(8) lvm.conf(5) lvmconfig(8)

pvchange(8) pvck(8) pvcreate(8) pvdisplay(8) pvmove(8) pvremove(8) pvresize(8) pvs(8) pvscan(8)

vgcfgbackup(8) vgcfgrestore(8) vgchange(8) vgck(8) vgcreate(8) vgconvert(8) vgdisplay(8) vgexport(8) vgextend(8) vgimport(8) vgimportclone(8) vgmerge(8) vgmknodes(8) vgreduce(8) vgremove(8) vgrename(8) vgs(8) vgscan(8) vgsplit(8)

lvcreate(8) lvchange(8) lvconvert(8) lvdisplay(8) lvextend(8) lvreduce(8) lvremove(8) lvrename(8) lvresize(8) lvs(8) lvscan(8)

lvm-fullreport(8) lvm-lvpoll(8) lvm2-activation-generator(8) blkdeactivate(8) lvmdump(8)

dmeventd(8) lvmetad(8) lvmpolld(8) lvmlockd(8) lvmlockctl(8) clvmd(8) cmirrord(8) lvmdbusd(8)

lvmsystemid(7) lvmreport(7) lvmraid(7) lvmthin(7) lvmcache(7)

Referenced By

lvchange(8), lvconvert(8), lvcreate(8), lvdisplay(8), lvextend(8), lvm(8), lvm2-activation-generator(8), lvmconfig(8), lvmdiskscan(8), lvmetad(8), lvm-fullreport(8), lvm-lvpoll(8), lvreduce(8), lvremove(8), lvrename(8), lvresize(8), lvs(8), lvscan(8), pvchange(8), pvck(8), pvcreate(8), pvdisplay(8), pvmove(8), pvremove(8), pvresize(8), pvs(8), vgcfgbackup(8), vgcfgrestore(8), vgchange(8), vgck(8), vgconvert(8), vgcreate(8), vgdisplay(8), vgexport(8), vgextend(8), vgimport(8), vgimportclone(8), vgmerge(8), vgmknodes(8), vgreduce(8), vgremove(8), vgrename(8), vgs(8), vgscan(8), vgsplit(8).

LVM TOOLS 2.02.172(2) (2017-06-28) Red Hat, Inc.