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192 lines
4.9 KiB
ReStructuredText
192 lines
4.9 KiB
ReStructuredText
===============================================
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rbd -- manage rados block device (RBD) images
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===============================================
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.. program:: rbd
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Synopsis
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========
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| **rbd** [ -c *ceph.conf* ] [ -m *monaddr* ] [ -p | --pool *pool* ] [
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--size *size* ] [ --order *bits* ] [ *command* ... ]
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Description
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===========
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**rbd** is a utility for manipulating rados block device (RBD) images,
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used by the Linux rbd driver and the rbd storage driver for Qemu/KVM.
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RBD images are simple block devices that are striped over objects and
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stored in a RADOS object store. The size of the objects the image is
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striped over must be a power of two.
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Options
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=======
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.. option:: -c ceph.conf, --conf ceph.conf
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Use ceph.conf configuration file instead of the default /etc/ceph/ceph.conf to
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determine monitor addresses during startup.
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.. option:: -m monaddress[:port]
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Connect to specified monitor (instead of looking through ceph.conf).
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.. option:: -p pool, --pool pool
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Interact with the given pool. Required by most commands.
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Parameters
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==========
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.. option:: --size size-in-mb
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Specifies the size (in megabytes) of the new rbd image.
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.. option:: --order bits
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Specifies the object size expressed as a number of bits, such that
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the object size is ``1 << order``. The default is 22 (4 MB).
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.. option:: --snap snap
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Specifies the snapshot name for the specific operation.
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.. option:: --user username
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Specifies the username to use with the map command.
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.. option:: --secret filename
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Specifies a file containing the secret to use with the map command.
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Commands
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========
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.. TODO rst "option" directive seems to require --foo style options, parsing breaks on subcommands.. the args show up as bold too
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:command:`ls` [*pool-name*]
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Will list all rbd images listed in the rbd_directory object.
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:command:`info` [*image-name*]
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Will dump information (such as size and order) about a specific rbd image.
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:command:`create` [*image-name*]
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Will create a new rbd image. You must also specify the size via --size.
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:command:`clone` [*parent-snapname*] [*image-name*]
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Will create a clone (copy-on-write child) of the parent snapshot.
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Size and object order will be identical to parent image unless specified.
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:command:`resize` [*image-name*]
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Resizes rbd image. The size parameter also needs to be specified.
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:command:`rm` [*image-name*]
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Deletes an rbd image (including all data blocks). If the image has
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snapshots, this fails and nothing is deleted.
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:command:`export` [*image-name*] [*dest-path*]
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Exports image to dest path.
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:command:`import` [*path*] [*dest-image*]
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Creates a new image and imports its data from path.
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:command:`cp` [*src-image*] [*dest-image*]
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Copies the content of a src-image into the newly created dest-image.
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:command:`mv` [*src-image*] [*dest-image*]
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Renames an image. Note: rename across pools is not supported.
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:command:`snap` ls [*image-name*]
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Dumps the list of snapshots inside a specific image.
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:command:`snap` create [*image-name*]
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Creates a new snapshot. Requires the snapshot name parameter specified.
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:command:`snap` rollback [*image-name*]
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Rollback image content to snapshot. This will iterate through the entire blocks
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array and update the data head content to the snapshotted version.
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:command:`snap` rm [*image-name*]
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Removes the specified snapshot.
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:command:`snap` purge [*image-name*]
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Removes all snapshots from an image.
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:command:`map` [*image-name*]
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Maps the specified image to a block device via the rbd kernel module.
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:command:`unmap` [*device-path*]
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Unmaps the block device that was mapped via the rbd kernel module.
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:command:`showmapped`
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Show the rbd images that are mapped via the rbd kernel module.
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Image name
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==========
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In addition to using the --pool and the --snap options, the image name can include both
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the pool name and the snapshot name. The image name format is as follows::
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[pool/]image-name[@snap]
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Thus an image name that contains a slash character ('/') requires specifying the pool
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name explicitly.
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Examples
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========
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To create a new rbd image that is 100 GB::
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rbd -p mypool create myimage --size 102400
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or alternatively::
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rbd create mypool/myimage --size 102400
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To use a non-default object size (8 MB)::
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rbd create mypool/myimage --size 102400 --order 23
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To delete an rbd image (be careful!)::
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rbd rm mypool/myimage
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To create a new snapshot::
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rbd snap create mypool/myimage@mysnap
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To create a copy-on-write clone of a snapshot::
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rbd clone myimage@mysnap cloneimage
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To delete a snapshot::
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rbd snap rm mypool/myimage@mysnap
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To map an image via the kernel with cephx enabled::
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rbd map myimage --user admin --secret secretfile
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To unmap an image::
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rbd unmap /dev/rbd0
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Availability
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============
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**rbd** is part of the Ceph distributed file system. Please refer to
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the Ceph documentation at http://ceph.com/docs for more information.
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See also
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========
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:doc:`ceph <ceph>`\(8),
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:doc:`rados <rados>`\(8)
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