ceph/doc/man/8/rbd.rst

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===============================================
rbd -- manage rados block device (RBD) images
===============================================
.. program:: rbd
Synopsis
========
| **rbd** [ -c *ceph.conf* ] [ -m *monaddr* ] [ -p | --pool *pool* ] [
--size *size* ] [ --order *bits* ] [ *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:: -p pool, --pool pool
Interact with the given pool. Required by most commands.
Parameters
==========
.. option:: --size size-in-mb
Specifies the size (in megabytes) of the new rbd image.
.. option:: --order bits
Specifies the object size expressed as a number of bits, such that
the object size is ``1 << order``. The default is 22 (4 MB).
.. option:: --snap snap
Specifies the snapshot name for the specific operation.
.. option:: --user username
Specifies the username to use with the map command.
.. option:: --secret filename
Specifies a file containing the secret to use with the map command.
Commands
========
.. TODO rst "option" directive seems to require --foo style options, parsing breaks on subcommands.. the args show up as bold too
:command:`ls` [*pool-name*]
Will list all rbd images listed in the rbd_directory object.
:command:`info` [*image-name*]
Will dump information (such as size and order) about a specific rbd image.
:command:`create` [*image-name*]
Will create a new rbd image. You must also specify the size via --size.
:command:`resize` [*image-name*]
Resizes rbd image. The size parameter also needs to be specified.
:command:`rm` [*image-name*]
Deletes an rbd image (including all data blocks). If the image has
snapshots, this fails and nothing is deleted.
:command:`export` [*image-name*] [*dest-path*]
Exports image to dest path.
:command:`import` [*path*] [*dest-image*]
Creates a new image and imports its data from path.
:command:`cp` [*src-image*] [*dest-image*]
Copies the content of a src-image into the newly created dest-image.
:command:`mv` [*src-image*] [*dest-image*]
Renames an image.
:command:`snap` ls [*image-name*]
Dumps the list of snapshots inside a specific image.
:command:`snap` create [*image-name*]
Creates a new snapshot. Requires the snapshot name parameter specified.
:command:`snap` rollback [*image-name*]
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 [*image-name*]
Removes the specified snapshot.
:command:`snap` purge [*image-name*]
Removes all snapshots from an image.
:command:`map` [*image-name*]
Maps the specified image to a block device via the rbd kernel module.
:command:`unmap` [*device-path*]
Unmaps 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.
Image name
==========
In addition to using the --pool and the --snap options, the image name can include both
the pool name and the snapshot name. The image name format is as follows::
[pool/]image-name[@snap]
Thus an image name that contains a slash character ('/') requires specifying the pool
name explicitly.
Examples
========
To create a new rbd image that is 100 GB::
rbd -p mypool create myimage --size 102400
or alternatively::
rbd create mypool/myimage --size 102400
To use a non-default object size (8 MB)::
rbd create mypool/myimage --size 102400 --order 23
To delete an rbd image (be careful!)::
rbd rm mypool/myimage
To create a new snapshot::
rbd create mypool/myimage@mysnap
To map an image via the kernel with cephx enabled::
rbd map myimage --user admin --secret secretfile
To unmap an image::
rbd unmap /dev/rbd0
Availability
============
**rbd** is part of the Ceph distributed file system. Please refer to
the Ceph wiki at http://ceph.newdream.net/wiki for more information.
See also
========
:doc:`ceph <ceph>`\(8),
:doc:`rados <rados>`\(8)