Your company here — click to reach over 10,000 unique daily visitors

rados - Man Page

rados object storage utility


rados [ options ] [ command ]


rados is a utility for interacting with a Ceph object storage cluster (RADOS), part of the Ceph distributed storage system.

Global Options

--object-locator object_locator

Set object_locator for operation.

-p pool, --pool pool

Interact with the given pool. Required by most commands.

--target-pool pool

Select target pool by name.


As an alternative to --pool, --pgid also allow users to specify the PG id to which the command will be directed. With this option, certain commands like ls allow users to limit the scope of the command to the given PG.

-N namespace, --namespace namespace

Specify the rados namespace to use for the object.


Use with ls to list objects in all namespaces. Put in CEPH_ARGS environment variable to make this the default.


Use with ls to list objects in default namespace. Takes precedence over --all in case --all is in environment.

-s snap, --snap snap

Read from the given pool snapshot. Valid for all pool-specific read operations.


Create the pool or directory that was specified.

-i infile

will specify an input file to be passed along as a payload with the command to the monitor cluster. This is only used for specific monitor commands.

-m monaddress[:port]

Connect to specified monitor (instead of looking through ceph.conf).

-b block_size

Set the block size for put/get/append ops and for write benchmarking.


Uses the striping API of rados rather than the default one. Available for stat, stat2, get, put, append, truncate, rm, ls and all xattr related operation.

-O object_size, --object-size object_size

Set the object size for put/get ops and for write benchmarking.


Set the max number of objects for write benchmarking.

--lock-cookie locker-cookie

Will set the lock cookie for acquiring advisory lock (lock get command). If the cookie is not empty, this option must be passed to lock break command to find the correct lock when releasing lock.


Use with cp to specify the locator of the new object.


Use with cp to specify the namespace of the new object.

Bench Options

-t N, --concurrent-ios=N

Set number of concurrent I/O operations.


Prefix output with date/time.


Do not verify contents of read objects.


Write contents to the objects.


Write contents to the omap.


Write contents to the extended attributes.

Load Gen Options


Total number of objects.


Min object size.


Max object size.


Min io size of operations.


Max io size of operations.


Max number of operations.


Max backlog size.


Percent of operations that are read.


Target throughput (in bytes).


Total time (in seconds).


At what boundary to align random op offsets.

Cache Pools Options


Include clones when doing flush or evict.

Omap Options

--omap-key-file file

Read the omap key from a file.

Generic Options

-c FILE, --conf FILE

Read configuration from the given configuration file.

--id ID

Set ID portion of my name.

-n TYPE.ID, --name TYPE.ID

Set cephx user name.

--cluster NAME

Set cluster name (default: ceph).

--setuser USER

Set uid to user or uid (and gid to user's gid).

--setgroup GROUP

Set gid to group or gid.


Show version and quit.

Global Commands


List object pools


Show utilization statistics, including disk usage (bytes) and object counts, over the entire system and broken down by pool.

list-inconsistent-pg pool

List inconsistent PGs in given pool.

list-inconsistent-obj pgid

List inconsistent objects in given PG.

list-inconsistent-snapset pgid

List inconsistent snapsets in given PG.

Pool Specific Commands

get name outfile

Read object name from the cluster and write it to outfile.

put name infile [--offset offset]

Write object name with start offset (default:0) to the cluster with contents from infile. Warning: The put command creates a single RADOS object, sized just as large as your input file. Unless your objects are of reasonable and consistent sizes, that is probably not what you want -- consider using RGW/S3, CephFS, or RBD instead.

append name infile

Append object name to the cluster with contents from infile.

rm [--force-full] name ...

Remove object(s) with name(s). With --force-full will remove when cluster is marked full.

listwatchers name

List the watchers of object name.

ls outfile

List objects in the given pool and write to outfile. Instead of --pool if --pgid will be specified, ls will only list the objects in the given PG.


List snapshots for given pool.

clonedata srcname dstname --object-locator key

Clone object byte data from srcname to dstname.  Both objects must be stored with the locator key key (usually either srcname or dstname).  Object attributes and omap keys are not copied or cloned.

mksnap foo

Create pool snapshot named foo.

rmsnap foo

Remove pool snapshot named foo.

bench seconds mode [ -b objsize ] [ -t threads ]

Benchmark for seconds. The mode can be write, seq, or rand. seq and rand are read benchmarks, either sequential or random. Before running one of the reading benchmarks, run a write benchmark with the --no-cleanup option. The default object size is 4 MB, and the default number of simulated threads (parallel writes) is 16. The --run-name <label> option is useful for benchmarking a workload test from multiple clients. The <label> is an arbitrary object name. It is "benchmark_last_metadata" by default, and is used as the underlying object name for "read" and "write" ops. Note: -b objsize option is valid only in write mode. Note: write and seq must be run on the same host otherwise the objects created by write will have names that will fail seq.

cleanup [ --run-name run_name ] [ --prefix prefix ]

Clean up a previous benchmark operation. Note: the default run-name is "benchmark_last_metadata"

listxattr name

List all extended attributes of an object.

getxattr name attr

Dump the extended attribute value of attr of an object.

setxattr name attr value

Set the value of attr in the extended attributes of an object.

rmxattr name attr

Remove attr from the extended attributes of an object.

stat name

Get stat (ie. mtime, size) of given object

stat2 name

Get stat (similar to stat, but with high precision time) of given object

listomapkeys name

List all the keys stored in the object map of object name.

listomapvals name

List all key/value pairs stored in the object map of object name. The values are dumped in hexadecimal.

getomapval [ --omap-key-file file ] name key [ out-file ]

Dump the hexadecimal value of key in the object map of object name. If the optional out-file argument is not provided, the value will be written to standard output.

setomapval [ --omap-key-file file ] name key [ value ]

Set the value of key in the object map of object name. If the optional value argument is not provided, the value will be read from standard input.

rmomapkey [ --omap-key-file file ] name key

Remove key from the object map of object name.

getomapheader name

Dump the hexadecimal value of the object map header of object name.

setomapheader name value

Set the value of the object map header of object name.

export filename

Serialize pool contents to a file or standard output.n"

import [--dry-run] [--no-overwrite] < filename | - >

Load pool contents from a file or standard input


To view cluster utilization:

rados df

To get a list object in pool foo sent to stdout:

rados -p foo ls -

To get a list of objects in PG 0.6:

rados --pgid 0.6 ls

To write an object:

rados -p foo put myobject blah.txt

To create a snapshot:

rados -p foo mksnap mysnap

To delete the object:

rados -p foo rm myobject

To read a previously snapshotted version of an object:

rados -p foo -s mysnap get myobject blah.txt.old

To list inconsistent objects in PG 0.6:

rados list-inconsistent-obj 0.6 --format=json-pretty


rados is part of Ceph, a massively scalable, open-source, distributed storage system. Please refer to the Ceph documentation at https://docs.ceph.com for more information.

See Also


Referenced By

librados-config(8), rbd(8).

Jul 09, 2024 dev Ceph