Provided by: ceph-common_17.2.0-0ubuntu4_amd64 
NAME
rbd - manage rados block device (RBD) images
SYNOPSIS
rbd [ -c ceph.conf ] [ -m monaddr ] [--cluster cluster-name]
[ -p | --pool pool ] [ command ... ]
DESCRIPTION
rbd is a utility for manipulating rados block device (RBD) images, used by the Linux rbd
driver and the rbd storage driver for QEMU/KVM. RBD images are simple block devices that
are striped over objects and stored in a RADOS object store. The size of the objects the
image is striped over must be a power of two.
OPTIONS
-c ceph.conf, --conf ceph.conf
Use ceph.conf configuration file instead of the default /etc/ceph/ceph.conf to
determine monitor addresses during startup.
-m monaddress[:port]
Connect to specified monitor (instead of looking through ceph.conf).
--cluster cluster-name
Use different cluster name as compared to default cluster name ceph.
-p pool-name, --pool pool-name
Interact with the given pool. Required by most commands.
--namespace namespace-name
Use a pre-defined image namespace within a pool
--no-progress
Do not output progress information (goes to standard error by default for some
commands).
PARAMETERS
--image-format format-id
Specifies which object layout to use. The default is 2.
• format 1 - (deprecated) Use the original format for a new rbd image. This format
is understood by all versions of librbd and the kernel rbd module, but does not
support newer features like cloning.
• format 2 - Use the second rbd format, which is supported by librbd since the
Bobtail release and the kernel rbd module since kernel 3.10 (except for "fancy"
striping, which is supported since kernel 4.17). This adds support for cloning
and is more easily extensible to allow more features in the future.
-s size-in-M/G/T, --size size-in-M/G/T
Specifies the size of the new rbd image or the new size of the existing rbd image
in M/G/T. If no suffix is given, unit M is assumed.
--object-size size-in-B/K/M
Specifies the object size in B/K/M. Object size will be rounded up the nearest
power of two; if no suffix is given, unit B is assumed. The default object size is
4M, smallest is 4K and maximum is 32M.
The default value can be changed with the configuration option rbd_default_order,
which takes a power of two (default object size is 2 ^ rbd_default_order).
--stripe-unit size-in-B/K/M
Specifies the stripe unit size in B/K/M. If no suffix is given, unit B is assumed.
See striping section (below) for more details.
--stripe-count num
Specifies the number of objects to stripe over before looping back to the first
object. See striping section (below) for more details.
--snap snap
Specifies the snapshot name for the specific operation.
--id username
Specifies the username (without the client. prefix) to use with the map command.
--keyring filename
Specifies a keyring file containing a secret for the specified user to use with the
map command. If not specified, the default keyring locations will be searched.
--keyfile filename
Specifies a file containing the secret key of --id user to use with the map
command. This option is overridden by --keyring if the latter is also specified.
--shared lock-tag
Option for lock add that allows multiple clients to lock the same image if they use
the same tag. The tag is an arbitrary string. This is useful for situations where
an image must be open from more than one client at once, like during live migration
of a virtual machine, or for use underneath a clustered file system.
--format format
Specifies output formatting (default: plain, json, xml)
--pretty-format
Make json or xml formatted output more human-readable.
-o krbd-options, --options krbd-options
Specifies which options to use when mapping or unmapping an image via the rbd
kernel driver. krbd-options is a comma-separated list of options (similar to
mount(8) mount options). See kernel rbd (krbd) options section below for more
details.
--read-only
Map the image read-only. Equivalent to -o ro.
--image-feature feature-name
Specifies which RBD format 2 feature should be enabled when creating an image.
Multiple features can be enabled by repeating this option multiple times. The
following features are supported:
• layering: layering support
• striping: striping v2 support
• exclusive-lock: exclusive locking support
• object-map: object map support (requires exclusive-lock)
• fast-diff: fast diff calculations (requires object-map)
• deep-flatten: snapshot flatten support
• journaling: journaled IO support (requires exclusive-lock)
• data-pool: erasure coded pool support
--image-shared
Specifies that the image will be used concurrently by multiple clients. This will
disable features that are dependent upon exclusive ownership of the image.
--whole-object
Specifies that the diff should be limited to the extents of a full object instead
of showing intra-object deltas. When the object map feature is enabled on an image,
limiting the diff to the object extents will dramatically improve performance since
the differences can be computed by examining the in-memory object map instead of
querying RADOS for each object within the image.
--limit
Specifies the limit for the number of snapshots permitted.
COMMANDS
bench --io-type <read | write | readwrite | rw> [--io-size size-in-B/K/M/G/T]
[--io-threads num-ios-in-flight] [--io-total size-in-B/K/M/G/T] [--io-pattern seq | rand]
[--rw-mix-read read proportion in readwrite] image-spec
Generate a series of IOs to the image and measure the IO throughput and latency.
If no suffix is given, unit B is assumed for both --io-size and --io-total.
Defaults are: --io-size 4096, --io-threads 16, --io-total 1G, --io-pattern seq,
--rw-mix-read 50.
children snap-spec
List the clones of the image at the given snapshot. This checks every pool, and
outputs the resulting poolname/imagename.
This requires image format 2.
clone [--object-size size-in-B/K/M] [--stripe-unit size-in-B/K/M --stripe-count num]
[--image-feature feature-name] [--image-shared] parent-snap-spec child-image-spec
Will create a clone (copy-on-write child) of the parent snapshot. Object size will
be identical to that of the parent image unless specified. Size will be the same as
the parent snapshot. The --stripe-unit and --stripe-count arguments are optional,
but must be used together.
The parent snapshot must be protected (see rbd snap protect). This requires image
format 2.
config global get config-entity key
Get a global-level configuration override.
config global list [--format plain | json | xml] [--pretty-format] config-entity
List global-level configuration overrides.
config global set config-entity key value
Set a global-level configuration override.
config global remove config-entity key
Remove a global-level configuration override.
config image get image-spec key
Get an image-level configuration override.
config image list [--format plain | json | xml] [--pretty-format] image-spec
List image-level configuration overrides.
config image set image-spec key value
Set an image-level configuration override.
config image remove image-spec key
Remove an image-level configuration override.
config pool get pool-name key
Get a pool-level configuration override.
config pool list [--format plain | json | xml] [--pretty-format] pool-name
List pool-level configuration overrides.
config pool set pool-name key value
Set a pool-level configuration override.
config pool remove pool-name key
Remove a pool-level configuration override.
cp (src-image-spec | src-snap-spec) dest-image-spec
Copy the content of a src-image into the newly created dest-image. dest-image will
have the same size, object size, and image format as src-image. Note: snapshots
are not copied, use deep cp command to include snapshots.
create (-s | --size size-in-M/G/T) [--image-format format-id] [--object-size
size-in-B/K/M] [--stripe-unit size-in-B/K/M --stripe-count num] [--thick-provision]
[--no-progress] [--image-feature feature-name]... [--image-shared] image-spec
Will create a new rbd image. You must also specify the size via --size. The
--stripe-unit and --stripe-count arguments are optional, but must be used together.
If the --thick-provision is enabled, it will fully allocate storage for the image
at creation time. It will take a long time to do. Note: thick provisioning
requires zeroing the contents of the entire image.
deep cp (src-image-spec | src-snap-spec) dest-image-spec
Deep copy the content of a src-image into the newly created dest-image. Dest-image
will have the same size, object size, image format, and snapshots as src-image.
device list [-t | --device-type device-type] [--format plain | json | xml] --pretty-format
Show the rbd images that are mapped via the rbd kernel module (default) or other
supported device.
device map [-t | --device-type device-type] [--cookie device-cookie] [--show-cookie]
[--read-only] [--exclusive] [-o | --options device-options] image-spec | snap-spec
Map the specified image to a block device via the rbd kernel module (default) or
other supported device (nbd on Linux or ggate on FreeBSD).
The --options argument is a comma separated list of device type specific options
(opt1,opt2=val,...).
device unmap [-t | --device-type device-type] [-o | --options device-options] image-spec |
snap-spec | device-path
Unmap the block device that was mapped via the rbd kernel module (default) or other
supported device.
The --options argument is a comma separated list of device type specific options
(opt1,opt2=val,...).
device attach [-t | --device-type device-type] --device device-path [--cookie
device-cookie] [--show-cookie] [--read-only] [--exclusive] [--force] [-o | --options
device-options] image-spec | snap-spec
Attach the specified image to the specified block device (currently only nbd on
Linux). This operation is unsafe and should not be normally used. In particular,
specifying the wrong image or the wrong block device may lead to data corruption as
no validation is performed by nbd kernel driver.
The --options argument is a comma separated list of device type specific options
(opt1,opt2=val,...).
device detach [-t | --device-type device-type] [-o | --options device-options] image-spec
| snap-spec | device-path
Detach the block device that was mapped or attached (currently only nbd on Linux).
This operation is unsafe and should not be normally used.
The --options argument is a comma separated list of device type specific options
(opt1,opt2=val,...).
diff [--from-snap snap-name] [--whole-object] image-spec | snap-spec
Dump a list of byte extents in the image that have changed since the specified
start snapshot, or since the image was created. Each output line includes the
starting offset (in bytes), the length of the region (in bytes), and either 'zero'
or 'data' to indicate whether the region is known to be zeros or may contain other
data.
du [-p | --pool pool-name] [image-spec | snap-spec] [--merge-snapshots]
Will calculate the provisioned and actual disk usage of all images and associated
snapshots within the specified pool. It can also be used against individual images
and snapshots.
If the RBD fast-diff feature is not enabled on images, this operation will require
querying the OSDs for every potential object within the image.
The --merge-snapshots will merge snapshots used space into their parent images.
encryption format image-spec format passphrase-file [--cipher-alg alg]
Formats image to an encrypted format. All data previously written to the image
will become unreadable. A cloned image cannot be formatted, although encrypted
images can be cloned. Supported formats: luks1, luks2. Supported cipher
algorithms: aes-128, aes-256 (default).
export [--export-format format (1 or 2)] (image-spec | snap-spec) [dest-path]
Export image to dest path (use - for stdout). The --export-format accepts '1' or
'2' currently. Format 2 allow us to export not only the content of image, but also
the snapshots and other properties, such as image_order, features.
export-diff [--from-snap snap-name] [--whole-object] (image-spec | snap-spec) dest-path
Export an incremental diff for an image to dest path (use - for stdout). If an
initial snapshot is specified, only changes since that snapshot are included;
otherwise, any regions of the image that contain data are included. The end
snapshot is specified using the standard --snap option or @snap syntax (see below).
The image diff format includes metadata about image size changes, and the start and
end snapshots. It efficiently represents discarded or 'zero' regions of the image.
feature disable image-spec feature-name...
Disable the specified feature on the specified image. Multiple features can be
specified.
feature enable image-spec feature-name...
Enable the specified feature on the specified image. Multiple features can be
specified.
flatten image-spec
If image is a clone, copy all shared blocks from the parent snapshot and make the
child independent of the parent, severing the link between parent snap and child.
The parent snapshot can be unprotected and deleted if it has no further dependent
clones.
This requires image format 2.
group create group-spec
Create a group.
group image add group-spec image-spec
Add an image to a group.
group image list group-spec
List images in a group.
group image remove group-spec image-spec
Remove an image from a group.
group ls [-p | --pool pool-name]
List rbd groups.
group rename src-group-spec dest-group-spec
Rename a group. Note: rename across pools is not supported.
group rm group-spec
Delete a group.
group snap create group-snap-spec
Make a snapshot of a group.
group snap list group-spec
List snapshots of a group.
group snap rm group-snap-spec
Remove a snapshot from a group.
group snap rename group-snap-spec snap-name
Rename group's snapshot.
group snap rollback group-snap-spec
Rollback group to snapshot.
image-meta get image-spec key
Get metadata value with the key.
image-meta list image-spec
Show metadata held on the image. The first column is the key and the second column
is the value.
image-meta remove image-spec key
Remove metadata key with the value.
image-meta set image-spec key value
Set metadata key with the value. They will displayed in image-meta list.
import [--export-format format (1 or 2)] [--image-format format-id] [--object-size
size-in-B/K/M] [--stripe-unit size-in-B/K/M --stripe-count num] [--image-feature
feature-name]... [--image-shared] src-path [image-spec]
Create a new image and imports its data from path (use - for stdin). The import
operation will try to create sparse rbd images if possible. For import from stdin,
the sparsification unit is the data block size of the destination image (object
size).
The --stripe-unit and --stripe-count arguments are optional, but must be used
together.
The --export-format accepts '1' or '2' currently. Format 2 allow us to import not
only the content of image, but also the snapshots and other properties, such as
image_order, features.
import-diff src-path image-spec
Import an incremental diff of an image and applies it to the current image. If the
diff was generated relative to a start snapshot, we verify that snapshot already
exists before continuing. If there was an end snapshot we verify it does not
already exist before applying the changes, and create the snapshot when we are
done.
info image-spec | snap-spec
Will dump information (such as size and object size) about a specific rbd image.
If image is a clone, information about its parent is also displayed. If a snapshot
is specified, whether it is protected is shown as well.
journal client disconnect journal-spec
Flag image journal client as disconnected.
journal export [--verbose] [--no-error] src-journal-spec path-name
Export image journal to path (use - for stdout). It can be make a backup of the
image journal especially before attempting dangerous operations.
Note that this command may not always work if the journal is badly corrupted.
journal import [--verbose] [--no-error] path-name dest-journal-spec
Import image journal from path (use - for stdin).
journal info journal-spec
Show information about image journal.
journal inspect [--verbose] journal-spec
Inspect and report image journal for structural errors.
journal reset journal-spec
Reset image journal.
journal status journal-spec
Show status of image journal.
lock add [--shared lock-tag] image-spec lock-id
Lock an image. The lock-id is an arbitrary name for the user's convenience. By
default, this is an exclusive lock, meaning it will fail if the image is already
locked. The --shared option changes this behavior. Note that locking does not
affect any operation other than adding a lock. It does not protect an image from
being deleted.
lock ls image-spec
Show locks held on the image. The first column is the locker to use with the lock
remove command.
lock rm image-spec lock-id locker
Release a lock on an image. The lock id and locker are as output by lock ls.
ls [-l | --long] [pool-name]
Will list all rbd images listed in the rbd_directory object. With -l, also show
snapshots, and use longer-format output including size, parent (if clone), format,
etc.
merge-diff first-diff-path second-diff-path merged-diff-path
Merge two continuous incremental diffs of an image into one single diff. The first
diff's end snapshot must be equal with the second diff's start snapshot. The first
diff could be - for stdin, and merged diff could be - for stdout, which enables
multiple diff files to be merged using something like 'rbd merge-diff first second
- | rbd merge-diff - third result'. Note this command currently only support the
source incremental diff with stripe_count == 1
migration abort image-spec
Cancel image migration. This step may be run after successful or failed migration
prepare or migration execute steps and returns the image to its initial (before
migration) state. All modifications to the destination image are lost.
migration commit image-spec
Commit image migration. This step is run after a successful migration prepare and
migration execute steps and removes the source image data.
migration execute image-spec
Execute image migration. This step is run after a successful migration prepare step
and copies image data to the destination.
migration prepare [--order order] [--object-size object-size] [--image-feature
image-feature] [--image-shared] [--stripe-unit stripe-unit] [--stripe-count stripe-count]
[--data-pool data-pool] [--import-only] [--source-spec json] [--source-spec-path path]
src-image-spec [dest-image-spec]
Prepare image migration. This is the first step when migrating an image, i.e.
changing the image location, format or other parameters that can't be changed
dynamically. The destination can match the source, and in this case dest-image-spec
can be omitted. After this step the source image is set as a parent of the
destination image, and the image is accessible in copy-on-write mode by its
destination spec.
An image can also be migrated from a read-only import source by adding the
--import-only optional and providing a JSON-encoded --source-spec or a path to a
JSON-encoded source-spec file using the --source-spec-path optionals.
mirror image demote image-spec
Demote a primary image to non-primary for RBD mirroring.
mirror image disable [--force] image-spec
Disable RBD mirroring for an image. If the mirroring is configured in image mode
for the image's pool, then it can be explicitly disabled mirroring for each image
within the pool.
mirror image enable image-spec mode
Enable RBD mirroring for an image. If the mirroring is configured in image mode for
the image's pool, then it can be explicitly enabled mirroring for each image within
the pool.
The mirror image mode can either be journal (default) or snapshot. The journal mode
requires the RBD journaling feature.
mirror image promote [--force] image-spec
Promote a non-primary image to primary for RBD mirroring.
mirror image resync image-spec
Force resync to primary image for RBD mirroring.
mirror image status image-spec
Show RBD mirroring status for an image.
mirror pool demote [pool-name]
Demote all primary images within a pool to non-primary. Every mirroring enabled
image will demoted in the pool.
mirror pool disable [pool-name]
Disable RBD mirroring by default within a pool. When mirroring is disabled on a
pool in this way, mirroring will also be disabled on any images (within the pool)
for which mirroring was enabled explicitly.
mirror pool enable [pool-name] mode
Enable RBD mirroring by default within a pool. The mirroring mode can either be
pool or image. If configured in pool mode, all images in the pool with the
journaling feature enabled are mirrored. If configured in image mode, mirroring
needs to be explicitly enabled (by mirror image enable command) on each image.
mirror pool info [pool-name]
Show information about the pool mirroring configuration. It includes mirroring
mode, peer UUID, remote cluster name, and remote client name.
mirror pool peer add [pool-name] remote-cluster-spec
Add a mirroring peer to a pool. remote-cluster-spec is [remote client name@]remote
cluster name.
The default for remote client name is "client.admin".
This requires mirroring mode is enabled.
mirror pool peer remove [pool-name] uuid
Remove a mirroring peer from a pool. The peer uuid is available from mirror pool
info command.
mirror pool peer set [pool-name] uuid key value
Update mirroring peer settings. The key can be either client or cluster, and the
value is corresponding to remote client name or remote cluster name.
mirror pool promote [--force] [pool-name]
Promote all non-primary images within a pool to primary. Every mirroring enabled
image will promoted in the pool.
mirror pool status [--verbose] [pool-name]
Show status for all mirrored images in the pool. With --verbose, also show
additionally output status details for every mirroring image in the pool.
mirror snapshot schedule add [-p | --pool pool] [--namespace namespace] [--image image]
interval [start-time]
Add mirror snapshot schedule.
mirror snapshot schedule list [-R | --recursive] [--format format] [--pretty-format] [-p |
--pool pool] [--namespace namespace] [--image image]
List mirror snapshot schedule.
mirror snapshot schedule remove [-p | --pool pool] [--namespace namespace] [--image image]
interval [start-time]
Remove mirror snapshot schedule.
mirror snapshot schedule status [-p | --pool pool] [--format format] [--pretty-format]
[--namespace namespace] [--image image]
Show mirror snapshot schedule status.
mv src-image-spec dest-image-spec
Rename an image. Note: rename across pools is not supported.
namespace create pool-name/namespace-name
Create a new image namespace within the pool.
namespace list pool-name
List image namespaces defined within the pool.
namespace remove pool-name/namespace-name
Remove an empty image namespace from the pool.
object-map check image-spec | snap-spec
Verify the object map is correct.
object-map rebuild image-spec | snap-spec
Rebuild an invalid object map for the specified image. An image snapshot can be
specified to rebuild an invalid object map for a snapshot.
pool init [pool-name] [--force]
Initialize pool for use by RBD. Newly created pools must initialized prior to use.
resize (-s | --size size-in-M/G/T) [--allow-shrink] image-spec
Resize rbd image. The size parameter also needs to be specified. The
--allow-shrink option lets the size be reduced.
rm image-spec
Delete an rbd image (including all data blocks). If the image has snapshots, this
fails and nothing is deleted.
snap create snap-spec
Create a new snapshot. Requires the snapshot name parameter specified.
snap limit clear image-spec
Remove any previously set limit on the number of snapshots allowed on an image.
snap limit set [--limit] limit image-spec
Set a limit for the number of snapshots allowed on an image.
snap ls image-spec
Dump the list of snapshots inside a specific image.
snap protect snap-spec
Protect a snapshot from deletion, so that clones can be made of it (see rbd clone).
Snapshots must be protected before clones are made; protection implies that there
exist dependent cloned children that refer to this snapshot. rbd clone will fail
on a nonprotected snapshot.
This requires image format 2.
snap purge image-spec
Remove all unprotected snapshots from an image.
snap rename src-snap-spec dest-snap-spec
Rename a snapshot. Note: rename across pools and images is not supported.
snap rm [--force] snap-spec
Remove the specified snapshot.
snap rollback snap-spec
Rollback image content to snapshot. This will iterate through the entire blocks
array and update the data head content to the snapshotted version.
snap unprotect snap-spec
Unprotect a snapshot from deletion (undo snap protect). If cloned children remain,
snap unprotect fails. (Note that clones may exist in different pools than the
parent snapshot.)
This requires image format 2.
sparsify [--sparse-size sparse-size] image-spec
Reclaim space for zeroed image extents. The default sparse size is 4096 bytes and
can be changed via --sparse-size option with the following restrictions: it should
be power of two, not less than 4096, and not larger than image object size.
status image-spec
Show the status of the image, including which clients have it open.
trash ls [pool-name]
List all entries from trash.
trash mv image-spec
Move an image to the trash. Images, even ones actively in-use by clones, can be
moved to the trash and deleted at a later time.
trash purge [pool-name]
Remove all expired images from trash.
trash restore image-id
Restore an image from trash.
trash rm image-id
Delete an image from trash. If image deferment time has not expired you can not
removed it unless use force. But an actively in-use by clones or has snapshots can
not be removed.
trash purge schedule add [-p | --pool pool] [--namespace namespace] interval [start-time]
Add trash purge schedule.
trash purge schedule list [-R | --recursive] [--format format] [--pretty-format] [-p |
--pool pool] [--namespace namespace]
List trash purge schedule.
trash purge schedule remove [-p | --pool pool] [--namespace namespace] interval
[start-time]
Remove trash purge schedule.
trash purge schedule status [-p | --pool pool] [--format format] [--pretty-format]
[--namespace namespace]
Show trash purge schedule status.
watch image-spec
Watch events on image.
IMAGE, SNAP, GROUP AND JOURNAL SPECS
image-spec is [pool-name/[namespace-name/]]image-name
snap-spec is [pool-name/[namespace-name/]]image-name@snap-name
group-spec is [pool-name/[namespace-name/]]group-name
group-snap-spec is [pool-name/[namespace-name/]]group-name@snap-name
journal-spec is [pool-name/[namespace-name/]]journal-name
The default for pool-name is "rbd" and namespace-name is "". If an image name contains a
slash character ('/'), pool-name is required.
The journal-name is image-id.
You may specify each name individually, using --pool, --namespace, --image, and --snap
options, but this is discouraged in favor of the above spec syntax.
STRIPING
RBD images are striped over many objects, which are then stored by the Ceph distributed
object store (RADOS). As a result, read and write requests for the image are distributed
across many nodes in the cluster, generally preventing any single node from becoming a
bottleneck when individual images get large or busy.
The striping is controlled by three parameters:
object-size
The size of objects we stripe over is a power of two. It will be rounded up the
nearest power of two. The default object size is 4 MB, smallest is 4K and maximum
is 32M.
stripe_unit
Each [stripe_unit] contiguous bytes are stored adjacently in the same object,
before we move on to the next object.
stripe_count
After we write [stripe_unit] bytes to [stripe_count] objects, we loop back to the
initial object and write another stripe, until the object reaches its maximum size.
At that point, we move on to the next [stripe_count] objects.
By default, [stripe_unit] is the same as the object size and [stripe_count] is 1.
Specifying a different [stripe_unit] and/or [stripe_count] is often referred to as using
"fancy" striping and requires format 2.
KERNEL RBD (KRBD) OPTIONS
Most of these options are useful mainly for debugging and benchmarking. The default
values are set in the kernel and may therefore depend on the version of the running
kernel.
Per client instance rbd device map options:
• fsid=aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee - FSID that should be assumed by the client.
• ip=a.b.c.d[:p] - IP and, optionally, port the client should use.
• share - Enable sharing of client instances with other mappings (default).
• noshare - Disable sharing of client instances with other mappings.
• crc - Enable CRC32C checksumming for msgr1 on-the-wire protocol (default). For msgr2.1
protocol this option is ignored: full checksumming is always on in 'crc' mode and always
off in 'secure' mode.
• nocrc - Disable CRC32C checksumming for msgr1 on-the-wire protocol. Note that only
payload checksumming is disabled, header checksumming is always on. For msgr2.1
protocol this option is ignored.
• cephx_require_signatures - Require msgr1 message signing feature (since 3.19, default).
This option is deprecated and will be removed in the future as the feature has been
supported since the Bobtail release.
• nocephx_require_signatures - Don't require msgr1 message signing feature (since 3.19).
This option is deprecated and will be removed in the future.
• tcp_nodelay - Disable Nagle's algorithm on client sockets (since 4.0, default).
• notcp_nodelay - Enable Nagle's algorithm on client sockets (since 4.0).
• cephx_sign_messages - Enable message signing for msgr1 on-the-wire protocol (since 4.4,
default). For msgr2.1 protocol this option is ignored: message signing is built into
'secure' mode and not offered in 'crc' mode.
• nocephx_sign_messages - Disable message signing for msgr1 on-the-wire protocol (since
4.4). For msgr2.1 protocol this option is ignored.
• mount_timeout=x - A timeout on various steps in rbd device map and rbd device unmap
sequences (default is 60 seconds). In particular, since 4.2 this can be used to ensure
that rbd device unmap eventually times out when there is no network connection to a
cluster.
• osdkeepalive=x - OSD keepalive timeout (default is 5 seconds).
• osd_idle_ttl=x - OSD idle TTL (default is 60 seconds).
Per mapping (block device) rbd device map options:
• rw - Map the image read-write (default). Overridden by --read-only.
• ro - Map the image read-only. Equivalent to --read-only.
• queue_depth=x - queue depth (since 4.2, default is 128 requests).
• lock_on_read - Acquire exclusive lock on reads, in addition to writes and discards
(since 4.9).
• exclusive - Disable automatic exclusive lock transitions (since 4.12). Equivalent to
--exclusive.
• lock_timeout=x - A timeout on waiting for the acquisition of exclusive lock (since 4.17,
default is 0 seconds, meaning no timeout).
• notrim - Turn off discard and write zeroes offload support to avoid deprovisioning a
fully provisioned image (since 4.17). When enabled, discard requests will fail with
-EOPNOTSUPP, write zeroes requests will fall back to manually zeroing.
• abort_on_full - Fail write requests with -ENOSPC when the cluster is full or the data
pool reaches its quota (since 5.0). The default behaviour is to block until the full
condition is cleared.
• alloc_size - Minimum allocation unit of the underlying OSD object store backend (since
5.1, default is 64K bytes). This is used to round off and drop discards that are too
small. For bluestore, the recommended setting is bluestore_min_alloc_size (typically
64K for hard disk drives and 16K for solid-state drives). For filestore with
filestore_punch_hole = false, the recommended setting is image object size (typically
4M).
• crush_location=x - Specify the location of the client in terms of CRUSH hierarchy (since
5.8). This is a set of key-value pairs separated from each other by '|', with keys
separated from values by ':'. Note that '|' may need to be quoted or escaped to avoid
it being interpreted as a pipe by the shell. The key is the bucket type name (e.g.
rack, datacenter or region with default bucket types) and the value is the bucket name.
For example, to indicate that the client is local to rack "myrack", data center "mydc"
and region "myregion":
crush_location=rack:myrack|datacenter:mydc|region:myregion
Each key-value pair stands on its own: "myrack" doesn't need to reside in "mydc", which
in turn doesn't need to reside in "myregion". The location is not a path to the root of
the hierarchy but rather a set of nodes that are matched independently, owning to the
fact that bucket names are unique within a CRUSH map. "Multipath" locations are
supported, so it is possible to indicate locality for multiple parallel hierarchies:
crush_location=rack:myrack1|rack:myrack2|datacenter:mydc
• read_from_replica=no - Disable replica reads, always pick the primary OSD (since 5.8,
default).
• read_from_replica=balance - When issued a read on a replicated pool, pick a random OSD
for serving it (since 5.8).
This mode is safe for general use only since Octopus (i.e. after "ceph osd
require-osd-release octopus"). Otherwise it should be limited to read-only workloads
such as images mapped read-only everywhere or snapshots.
• read_from_replica=localize - When issued a read on a replicated pool, pick the most
local OSD for serving it (since 5.8). The locality metric is calculated against the
location of the client given with crush_location; a match with the lowest-valued bucket
type wins. For example, with default bucket types, an OSD in a matching rack is closer
than an OSD in a matching data center, which in turn is closer than an OSD in a matching
region.
This mode is safe for general use only since Octopus (i.e. after "ceph osd
require-osd-release octopus"). Otherwise it should be limited to read-only workloads
such as images mapped read-only everywhere or snapshots.
• compression_hint=none - Don't set compression hints (since 5.8, default).
• compression_hint=compressible - Hint to the underlying OSD object store backend that the
data is compressible, enabling compression in passive mode (since 5.8).
• compression_hint=incompressible - Hint to the underlying OSD object store backend that
the data is incompressible, disabling compression in aggressive mode (since 5.8).
• ms_mode=legacy - Use msgr1 on-the-wire protocol (since 5.11, default).
• ms_mode=crc - Use msgr2.1 on-the-wire protocol, select 'crc' mode, also referred to as
plain mode (since 5.11). If the daemon denies 'crc' mode, fail the connection.
• ms_mode=secure - Use msgr2.1 on-the-wire protocol, select 'secure' mode (since 5.11).
'secure' mode provides full in-transit encryption ensuring both confidentiality and
authenticity. If the daemon denies 'secure' mode, fail the connection.
• ms_mode=prefer-crc - Use msgr2.1 on-the-wire protocol, select 'crc' mode (since 5.11).
If the daemon denies 'crc' mode in favor of 'secure' mode, agree to 'secure' mode.
• ms_mode=prefer-secure - Use msgr2.1 on-the-wire protocol, select 'secure' mode (since
5.11). If the daemon denies 'secure' mode in favor of 'crc' mode, agree to 'crc' mode.
• rxbounce - Use a bounce buffer when receiving data (since 5.17). The default behaviour
is to read directly into the destination buffer. A bounce buffer is needed if the
destination buffer isn't guaranteed to be stable (i.e. remain unchanged while it is
being read to). In particular this is the case for Windows where a system-wide "dummy"
(throwaway) page may be mapped into the destination buffer in order to generate a single
large I/O. Otherwise, "libceph: ... bad crc/signature" or "libceph: ... integrity
error, bad crc" errors and associated performance degradation are expected.
• udev - Wait for udev device manager to finish executing all matching "add" rules and
release the device before exiting (default). This option is not passed to the kernel.
• noudev - Don't wait for udev device manager. When enabled, the device may not be fully
usable immediately on exit.
rbd device unmap options:
• force - Force the unmapping of a block device that is open (since 4.9). The driver will
wait for running requests to complete and then unmap; requests sent to the driver after
initiating the unmap will be failed.
• udev - Wait for udev device manager to finish executing all matching "remove" rules and
clean up after the device before exiting (default). This option is not passed to the
kernel.
• noudev - Don't wait for udev device manager.
EXAMPLES
To create a new rbd image that is 100 GB:
rbd create mypool/myimage --size 102400
To use a non-default object size (8 MB):
rbd create mypool/myimage --size 102400 --object-size 8M
To delete an rbd image (be careful!):
rbd rm mypool/myimage
To create a new snapshot:
rbd snap create mypool/myimage@mysnap
To create a copy-on-write clone of a protected snapshot:
rbd clone mypool/myimage@mysnap otherpool/cloneimage
To see which clones of a snapshot exist:
rbd children mypool/myimage@mysnap
To delete a snapshot:
rbd snap rm mypool/myimage@mysnap
To map an image via the kernel with cephx enabled:
rbd device map mypool/myimage --id admin --keyfile secretfile
To map an image via the kernel with different cluster name other than default ceph:
rbd device map mypool/myimage --cluster cluster-name
To unmap an image:
rbd device unmap /dev/rbd0
To create an image and a clone from it:
rbd import --image-format 2 image mypool/parent
rbd snap create mypool/parent@snap
rbd snap protect mypool/parent@snap
rbd clone mypool/parent@snap otherpool/child
To create an image with a smaller stripe_unit (to better distribute small writes in some
workloads):
rbd create mypool/myimage --size 102400 --stripe-unit 65536B --stripe-count 16
To change an image from one image format to another, export it and then import it as the
desired image format:
rbd export mypool/myimage@snap /tmp/img
rbd import --image-format 2 /tmp/img mypool/myimage2
To lock an image for exclusive use:
rbd lock add mypool/myimage mylockid
To release a lock:
rbd lock remove mypool/myimage mylockid client.2485
To list images from trash:
rbd trash ls mypool
To defer delete an image (use --expires-at to set expiration time, default is now):
rbd trash mv mypool/myimage --expires-at "tomorrow"
To delete an image from trash (be careful!):
rbd trash rm mypool/myimage-id
To force delete an image from trash (be careful!):
rbd trash rm mypool/myimage-id --force
To restore an image from trash:
rbd trash restore mypool/myimage-id
To restore an image from trash and rename it:
rbd trash restore mypool/myimage-id --image mynewimage
AVAILABILITY
rbd 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
ceph(8), rados(8)
COPYRIGHT
2010-2022, Inktank Storage, Inc. and contributors. Licensed under Creative Commons
Attribution Share Alike 3.0 (CC-BY-SA-3.0)