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author | 2018-01-04 13:43:33 +0800 | |
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committer | 2018-01-05 11:59:39 +0800 | |
commit | 812ff6ca9fcd3e629e49d4328905f33eee8ca3f5 (patch) | |
tree | 04ece7b4da00d9d2f98093774594f4057ae561d4 /src/ceph/doc/man/8/rbd.rst | |
parent | 15280273faafb77777eab341909a3f495cf248d9 (diff) |
initial code repo
This patch creates initial code repo.
For ceph, luminous stable release will be used for base code,
and next changes and optimization for ceph will be added to it.
For opensds, currently any changes can be upstreamed into original
opensds repo (https://github.com/opensds/opensds), and so stor4nfv
will directly clone opensds code to deploy stor4nfv environment.
And the scripts for deployment based on ceph and opensds will be
put into 'ci' directory.
Change-Id: I46a32218884c75dda2936337604ff03c554648e4
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
Diffstat (limited to 'src/ceph/doc/man/8/rbd.rst')
-rw-r--r-- | src/ceph/doc/man/8/rbd.rst | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/src/ceph/doc/man/8/rbd.rst b/src/ceph/doc/man/8/rbd.rst new file mode 100644 index 0000000..c37ca44 --- /dev/null +++ b/src/ceph/doc/man/8/rbd.rst @@ -0,0 +1,615 @@ +:orphan: + +=============================================== + rbd -- manage rados block device (RBD) images +=============================================== + +.. program:: rbd + +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 +======= + +.. option:: -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. + +.. option:: -m monaddress[:port] + + Connect to specified monitor (instead of looking through ceph.conf). + +.. option:: --cluster cluster-name + + Use different cluster name as compared to default cluster name *ceph*. + +.. option:: -p pool-name, --pool pool-name + + Interact with the given pool. Required by most commands. + +.. option:: --no-progress + + Do not output progress information (goes to standard error by + default for some commands). + + +Parameters +========== + +.. option:: --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 and kernel since version 3.11 (except for striping). This adds + support for cloning and is more easily extensible to allow more + features in the future. + +.. option:: -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. + +.. option:: --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. + +.. option:: --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. + +.. option:: --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. + +.. option:: --snap snap + + Specifies the snapshot name for the specific operation. + +.. option:: --id username + + Specifies the username (without the ``client.`` prefix) to use with the map command. + +.. option:: --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. + +.. option:: --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. + +.. option:: --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 filesystem. + +.. option:: --format format + + Specifies output formatting (default: plain, json, xml) + +.. option:: --pretty-format + + Make json or xml formatted output more human-readable. + +.. option:: -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. + +.. option:: --read-only + + Map the image read-only. Equivalent to -o ro. + +.. option:: --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) + +.. option:: --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. + +.. option:: --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. + +.. option:: --limit + + Specifies the limit for the number of snapshots permitted. + +Commands +======== + +.. TODO rst "option" directive seems to require --foo style options, parsing breaks on subcommands.. the args show up as bold too + +:command:`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. + +:command:`du` [-p | --pool *pool-name*] [*image-spec* | *snap-spec*] + 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. + +:command:`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. + +:command:`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*] [--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. + +:command:`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. + +:command:`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. + +:command:`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. + +:command:`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. + +:command:`rm` *image-spec* + Delete an rbd image (including all data blocks). If the image has + snapshots, this fails and nothing is deleted. + +:command:`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. + +:command:`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. + +:command:`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. + +:command:`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 + +:command:`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. + +:command:`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. + +:command:`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. + +:command:`mv` *src-image-spec* *dest-image-spec* + Rename an image. Note: rename across pools is not supported. + +:command:`image-meta list` *image-spec* + Show metadata held on the image. The first column is the key + and the second column is the value. + +:command:`image-meta get` *image-spec* *key* + Get metadata value with the key. + +:command:`image-meta set` *image-spec* *key* *value* + Set metadata key with the value. They will displayed in `image-meta list`. + +:command:`image-meta remove` *image-spec* *key* + Remove metadata key with the value. + +:command:`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. + +:command:`snap ls` *image-spec* + Dump the list of snapshots inside a specific image. + +:command:`snap create` *snap-spec* + Create a new snapshot. Requires the snapshot name parameter specified. + +:command:`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. + +:command:`snap rm` [--force] *snap-spec* + Remove the specified snapshot. + +:command:`snap purge` *image-spec* + Remove all snapshots from an image. + +:command:`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. + +:command:`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. + +:command:`snap limit set` [--limit] *limit* *image-spec* + Set a limit for the number of snapshots allowed on an image. + +:command:`snap limit clear` *image-spec* + Remove any previously set limit on the number of snapshots allowed on + an image. + +:command:`map` [-o | --options *krbd-options* ] [--read-only] *image-spec* | *snap-spec* + Map the specified image to a block device via the rbd kernel module. + +:command:`unmap` [-o | --options *krbd-options* ] *image-spec* | *snap-spec* | *device-path* + Unmap the block device that was mapped via the rbd kernel module. + +:command:`showmapped` + Show the rbd images that are mapped via the rbd kernel module. + +:command:`nbd map` [--device *device-path*] [--read-only] *image-spec* | *snap-spec* + Map the specified image to a block device via the rbd-nbd tool. + +:command:`nbd unmap` *device-path* + Unmap the block device that was mapped via the rbd-nbd tool. + +:command:`nbd list` + Show the list of used nbd devices via the rbd-nbd tool. + +:command:`status` *image-spec* + Show the status of the image, including which clients have it open. + +:command:`feature disable` *image-spec* *feature-name*... + Disable the specified feature on the specified image. Multiple features can + be specified. + +:command:`feature enable` *image-spec* *feature-name*... + Enable the specified feature on the specified image. Multiple features can + be specified. + +:command:`lock list` *image-spec* + Show locks held on the image. The first column is the locker + to use with the `lock remove` command. + +:command:`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. + +:command:`lock remove` *image-spec* *lock-id* *locker* + Release a lock on an image. The lock id and locker are + as output by lock ls. + +:command:`bench` --io-type <read | write> [--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] *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. + +:command:`trash ls` [*pool-name*] + List all entries from trash. + +:command:`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. + +:command:`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. + +:command:`trash restore` *image-id* + Restore an image from trash. + +Image and snap specs +==================== + +| *image-spec* is [*pool-name*]/*image-name* +| *snap-spec* is [*pool-name*]/*image-name*\ @\ *snap-name* + +The default for *pool-name* is "rbd". If an image name contains a slash +character ('/'), *pool-name* is required. + +You may specify each name individually, using --pool, --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: + +.. option:: 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. + +.. option:: stripe_unit + + Each [*stripe_unit*] contiguous bytes are stored adjacently in the same object, before we move on + to the next object. + +.. option:: 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*] requires that the STRIPINGV2 feature be supported (added in Ceph v0.53) and format 2 images be +used. + + +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 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 data writes (default). + +* nocrc - Disable CRC32C checksumming for data writes. + +* cephx_require_signatures - Require cephx message signing (since 3.19, + default). + +* nocephx_require_signatures - Don't require cephx message signing (since + 3.19). + +* 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 (since 4.4, default). + +* nocephx_sign_messages - Disable message signing (since 4.4). + +* mount_timeout=x - A timeout on various steps in `rbd map` and `rbd unmap` + sequences (default is 60 seconds). In particular, since 4.2 this can be used + to ensure that `rbd 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 map` options: + +* rw - Map the image read-write (default). + +* 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). + +`rbd 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. + + +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 map mypool/myimage --id admin --keyfile secretfile + +To map an image via the kernel with different cluster name other than default *ceph*:: + + rbd map mypool/myimage --cluster cluster-name + +To unmap an image:: + + rbd 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 *--delay* to set delay-time, default is 0):: + + rbd trash mv mypool/myimage + +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 http://ceph.com/docs for more information. + + +See also +======== + +:doc:`ceph <ceph>`\(8), +:doc:`rados <rados>`\(8) |