注意

本文档适用于 Ceph 的开发版本。

rbd -- manage rados block device (RBD) images

概要

rbd [ -c ceph.conf ] [ -m monaddr ] [--cluster cluster-name] [ -p | --pool pool ] [ command … ]

描述

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.

选项

-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 池名。, --pool 池名。

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 格式

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] 图像规范

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 快照规范

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 图像规范 key

Get an image-level configuration override.

config image list [--format plain | json | xml] [--pretty-format] 图像规范

List image-level configuration overrides.

config image set 图像规范 key value

Set an image-level configuration override.

config image remove 图像规范 key

Remove an image-level configuration override.

config pool get 池名。 key

Get a pool-level configuration override.

config pool list [--format plain | json | xml] [--pretty-format] 池名。

List pool-level configuration overrides.

config pool set 池名。 key value

Set a pool-level configuration override.

config pool remove 池名。 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] 图像规范

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] [--snap-id 快照id] [--read-only] [--exclusive] [-o | --options device-options] 图像规范 | 快照规范

Map the specified image to a block device via the rbd kernel module (default) or other supported device (nbd or ubbd 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] [--snap-id快照id] 图像规范 | 快照规范 | 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] [--snap-id 快照id] [--read-only] [--exclusive] [--force] [-o | --options device-options] 图像规范 | 快照规范

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] [--snap-id快照id] 图像规范 | 快照规范 | 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 快照名] [--whole-object] 图像规范 | 快照规范

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 池名。] [图像规范 | 快照规范] [--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 图像规范 格式 密钥文件 [--cipher-alg alg]

Formats image to an encrypted format. All data previously written to the image will become unreadable. Supported formats: luks1, luks2. Supported cipher algorithms: aes-128, aes-256 (default).

export [--export-format format (1 or 2)] (图像规范 | 快照规范) [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 快照名] [--whole-object] (图像规范 | 快照规范) 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 图像规范 feature-name…

Disable the specified feature on the specified image. Multiple features can be specified.

feature enable 图像规范 feature-name…

Enable the specified feature on the specified image. Multiple features can be specified.

flatten [--encryption-format encryption-format--encryption-passphrase-file密钥文件]… 图像规范

If the 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 图像规范

Add an image to a group.

group image list group-spec

List images in a group.

group image remove group-spec 图像规范

Remove an image from a group.

group ls [-p | --pool 池名。]

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 info group-snap-spec

Get information about a snapshot of a group.

group snap rm group-snap-spec

Remove a snapshot from a group.

group snap rename group-snap-spec 快照名

Rename group’s snapshot.

group snap rollback group-snap-spec

Rollback group to snapshot.

image-meta get 图像规范 key

Get metadata value with the key.

image-meta list 图像规范

Show metadata held on the image. The first column is the key and the second column is the value.

image-meta remove 图像规范 key

Remove metadata key with the value.

image-meta set 图像规范 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 [图像规范]

Create a new image and import 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 图像规范

Import an incremental diff of an image and apply 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 图像规范 | 快照规范

Will dump information (such as size and object size) about a specific rbd image. If the 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] 图像规范 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 图像规范

Show locks held on the image. The first column is the locker to use with the lock remove command.

lock rm 图像规范 lock-id locker

Release a lock on an image. The lock id and locker are as output by lock ls.

ls [-l | --long] [池名。]

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 图像规范

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 图像规范

Commit image migration. This step is run after successful migration prepare and migration execute steps and removes the source image data.

migration execute 图像规范

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 图像规范

Demote a primary image to non-primary for RBD mirroring.

mirror image disable [--force] 图像规范

Disable RBD mirroring for an image. If the mirroring is configured in image mode for the image’s pool, then it must be disabled for each image individually.

mirror image enable 图像规范 mode

Enable RBD mirroring for an image. If the mirroring is configured in image mode for the image’s pool, then it must be enabled for each image individually.

The mirror image mode can either be journal (default) or snapshot. The journal mode requires the RBD journaling feature.

mirror image promote [--force] 图像规范

Promote a non-primary image to primary for RBD mirroring.

mirror image resync 图像规范

Force resync to primary image for RBD mirroring.

mirror image status 图像规范

Show RBD mirroring status for an image.

mirror pool demote [池名。]

Demote all primary images within a pool or namespace to non-primary. Every mirror-enabled image in the pool or namespace will be demoted.

mirror pool disable [池名。]

Disable RBD mirroring within a pool or namespace. When mirroring is disabled on a pool or namespace in this way, mirroring will also be disabled on all images (within the pool or namespace) for which mirroring was enabled, whether by default or explicitly.

mirror pool enable 池名。 mode [--remote-namespace remote-namespace-name]

Enable RBD mirroring within a pool or namespace. The mirroring mode can either be pool or image. If configured in pool mode, all images in the pool or namespace 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. A namespace can be mirrored to a different namespace on the remote pool using the --remote-namespace option.

mirror pool info [池名。]

Show information about the pool or namespace mirroring configuration. For both pools and namespaces, it includes the mirroring mode, mirror UUID and remote namespace. For pools, it additionally includes the site name, peer UUID, remote cluster name, and remote client name.

mirror pool peer add [池名。] remote-cluster-spec

Add a mirroring peer to a pool. remote-cluster-spec是 [remote client name@]remote cluster name.

默认的remote client name is “client.admin”.

This requires mirroring to be enabled on the pool.

mirror pool peer remove [池名。] uuid

Remove a mirroring peer from a pool. The peer UUID is available from mirror pool info command.

mirror pool peer set [池名。] 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] [池名。]

Promote all non-primary images within a pool or namespace to primary. Every mirror-enabled image in the pool or namespace will be promoted.

mirror pool status [--verbose] [池名。]

Show status for all mirrored images in the pool or namespace. With --verbose, show additional output status details for every mirror-enabled image in the pool or namespace.

mirror snapshot schedule add [-p | --pool pool] [--namespace namespace] [--image image] interval [start-time]

Add mirror snapshot schedule. The interval can be specified in days, hours, or minutes using the d, h, m suffix respectively. The start-time is a time string in ISO 8601 format. Not providing the --pool, --namespace和--image options creates a global schedule which applies to all mirror-enabled images in the cluster.

mirror snapshot schedule list [-R | --recursive] [--format 格式] [--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 格式] [--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 池名。/namespace-name

Create a new image namespace within the pool.

namespace list 池名。

List image namespaces defined within the pool.

namespace remove 池名。/namespace-name

Remove an empty image namespace from the pool.

object-map check 图像规范 | 快照规范

Verify the object map is correct.

object-map rebuild 图像规范 | 快照规范

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 [池名。] [--force]

Initialize pool for use by RBD. Newly created pools must be initialized prior to use.

resize (-s | --size size-in-M/G/T) [--allow-shrink] [--encryption-format encryption-format--encryption-passphrase-file密钥文件]… 图像规范

Resize rbd image. The size parameter also needs to be specified. The --allow-shrink option lets the size be reduced.

rm 图像规范

Delete an rbd image (including all data blocks). If the image has snapshots, this fails and nothing is deleted.

snap create 快照规范

Create a new snapshot. Requires the snapshot name parameter to be specified.

snap limit clear 图像规范

Remove any previously set limit on the number of snapshots allowed on an image.

snap limit set [--limit] 限制 图像规范

Set a limit for the number of snapshots allowed on an image.

snap ls 图像规范

Dump the list of snapshots of a specific image.

snap protect 快照规范

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 图像规范

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] 快照规范

Remove the specified snapshot.

snap rollback 快照规范

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 快照规范

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] 图像规范

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 图像规范

Show the status of the image, including which clients have it open.

trash ls [池名。]

List all entries from trash.

trash mv [--expires-at <expires-at>] 图像规范

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. Use --expires-at to set the expiration time of an image after which it’s allowed to be removed.

trash purge [池名。]

Remove all expired images from trash.

trash restore image-id

Restore an image from trash.

trash rm [--force] image-id

Delete an image from trash. If the image deferment time has not expired it can be removed using --force. An image that is actively in-use by clones or has snapshots cannot 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 格式] [--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 格式] [--pretty-format] [--namespace namespace]

Show trash purge schedule status.

watch 图像规范

Watch events on image.

Image, snap, group and journal specs

图像规范是 [池名。/[namespace-name/]]图像名
快照规范是 [池名。/[namespace-name/]]图像名@快照名
group-spec是 [池名。/[namespace-name/]]group-name
group-snap-spec是 [池名。/[namespace-name/]]group-name@快照名
journal-spec是 [池名。/[namespace-name/]]journal-name

默认的池名。 is “rbd” and namespace-name is “”. If an image name contains a slash character (‘/’), 池名。 is required.

The 9b591a: Ceph 对象存储 9dbb5f: (又名 RGW) 服务提供与 Amazon S3 和 OpenStack Swift 兼容的 RESTful API 接口。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.

stripe-unit

Each [stripe-unit] contiguous bytes are stored adjacently in the same object, before we move on

stripe-count

After we write [stripe-unit] bytes to [stripe-count] objects, we loop back to the initial objectstripe-count] objects.

By default, [stripe-unit] is the same as the object size and [stripe-count] is 1. Specifying a differentstripe-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

Per client instancerbd device mapoptions:

  • fsid=aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee - FSID that should be assumed by

  • 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).

  • nocrc - Disable CRC32C checksumming for msgr1 on-the-wire protocol. Note

  • cephx_require_signatures - Require msgr1 message signing feature (since 3.19,

  • nocephx_require_signatures - Don’t require msgr1 message signing feature

  • tcp_nodelay - Disable Nagle’s algorithm on client sockets (since 4.0,

  • notcp_nodelay - Enable Nagle’s algorithm on client sockets (since 4.0).

  • cephx_sign_messages - Enable message signing for msgr1 on-the-wire protocol

  • nocephx_sign_messages - Disable message signing for msgr1 on-the-wire protocol

  • mount_timeout=x - A timeout on various steps inrbd device map和rbd device unmapsequences (default is 60 seconds). In particular,rbd device unmapeventually

  • 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 mapoptions:

  • 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

  • exclusive - Disable automatic exclusive lock transitions (since 4.12).

  • lock_timeout=x - A timeout on waiting for the acquisition of exclusive lock

  • notrim - Turn off discard and write zeroes offload support to avoid

  • abort_on_full - Fail write requests with -ENOSPC when the cluster is full or

  • alloc_size - Minimum allocation unit of the underlying OSD object store

  • crush_location=x - Specify the location of the client in terms of CRUSH

    crush_location=rack:myrack|datacenter:mydc|region:myregion

    Each key-value pair stands on its own: “myrack” doesn't need to reside in

    crush_location=rack:myrack1|rack:myrack2|datacenter:mydc

  • read_from_replica=no - Disable replica reads, always pick the primary OSD

  • read_from_replica=balance - When issued a read on a replicated pool, pick

    This mode is safe for general use only since Octopus (i.e. after “ceph osd

  • read_from_replica=localize - When issued a read on a replicated pool, pick

    This mode is safe for general use only since Octopus (i.e. after “ceph osd

  • compression_hint=none - Don’t set compression hints (since 5.8, default).

  • compression_hint=compressible - Hint to the underlying OSD object store

  • compression_hint"incompressible" - Hint to the underlying OSD object store

  • 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

  • ms_mode=secure - Use msgr2.1 on-the-wire protocol, select ‘secure’ mode

  • ms_mode=prefer-crc - Use msgr2.1 on-the-wire protocol, select ‘crc’

  • ms_mode=prefer-secure - Use msgr2.1 on-the-wire protocol, select ‘secure’

  • rxbounce - Use a bounce buffer when receiving data (since 5.17). The default

  • udev - Wait for udev device manager to finish executing all matching

  • noudev - Don’t wait for udev device manager. When enabled, the device may

rbd device unmapoptions:

  • force - Force the unmapping of a block device that is open (since 4.9). The

  • udev - Wait for udev device manager to finish executing all matching

  • 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 defaultceph:

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

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-atto 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

To create a mirror snapshot schedule for an image:

rbd mirror snapshot schedule add --pool mypool --image myimage 12h 14:00:00-05:00

可用性

rbd是Ceph的一部分，Ceph是一个大规模可扩展、开源的分布式存储系统。请参阅https://docs.ceph.com中的Ceph文档以获取更多信息。

参见

ceph(8),rados(8)

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