Provided by: ceph-common_10.2.11-0ubuntu0.16.04.3_amd64 bug

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.

       --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  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.

       -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.

       --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 filesystem.

       --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)

       --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.

COMMANDS

       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.

       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 isn't enabled on images, this operation  will  require
              querying the OSDs for every potential object within the image.

       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.

       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.

       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.

       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.

       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.

       resize (-s | --size size-in-M/G/T) [--allow-shrink] image-spec
              Resizes   rbd   image.  The  size  parameter  also  needs  to  be  specified.   The
              --allow-shrink option lets the size be reduced.

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

       export (image-spec | snap-spec) [dest-path]
              Exports image to dest path (use - for stdout).

       import    [--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]
              Creates  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.

       export-diff [--from-snap snap-name] [--whole-object] (image-spec | snap-spec) dest-path
              Exports  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.

       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

       import-diff src-path image-spec
              Imports  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.

       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.

       cp (src-image-spec | src-snap-spec) dest-image-spec
              Copies  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.

       mv src-image-spec dest-image-spec
              Renames an image.  Note: rename across pools is not supported.

       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 get image-spec key
              Get metadata value with the key.

       image-meta set image-spec key value
              Set metadata key with the value. They will displayed in image-meta list.

       image-meta remove image-spec key
              Remove metadata key with the value.

       object-map rebuild image-spec | snap-spec
              Rebuilds  an  invalid  object map for the specified image. An image snapshot can be
              specified to rebuild an invalid object map for a snapshot.

       snap ls image-spec
              Dumps the list of snapshots inside a specific image.

       snap create snap-spec
              Creates a new snapshot. Requires the snapshot name parameter specified.

       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 rm snap-spec
              Removes the specified snapshot.

       snap purge image-spec
              Removes all snapshots from an 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 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.

       map [-o | --options krbd-options ] [--read-only] image-spec | snap-spec
              Maps the specified image to a block device via the rbd kernel module.

       unmap [-o | --options krbd-options ] image-spec | snap-spec | device-path
              Unmaps the block device that was mapped via the rbd kernel module.

       showmapped
              Show the rbd images that are mapped via the rbd kernel module.

       nbd map [--device device-path] [--read-only] image-spec | snap-spec
              Maps the specified image to a block device via the rbd-nbd tool.

       nbd unmap device-path
              Unmaps the block device that was mapped via the rbd-nbd tool.

       nbd list
              Show the list of used nbd devices via the rbd-nbd tool.

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

       feature disable image-spec feature-name...
              Disables the specified feature on the specified image.  Multiple  features  can  be
              specified.

       feature enable image-spec feature-name...
              Enables  the  specified  feature  on  the specified image. Multiple features can be
              specified.

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

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

       bench-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 writes to the image  and  measure  the  write  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.

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:

       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] 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).

       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

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

       ceph(8), rados(8)

COPYRIGHT

       2010-2014,  Inktank  Storage,  Inc.  and  contributors.  Licensed  under  Creative Commons
       Attribution Share Alike 3.0 (CC-BY-SA-3.0)