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rbd

NAME

rbd - manage rados block device (RBD) images

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

-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).

-p pool, --pool pool

Interact with the given pool. Required by most commands.

PARAMETERS

--size size-in-mb

Specifies the size (in megabytes) of the new rbd image.

--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).

--snap snap

Specifies the snapshot name for the specific operation.

COMMANDS

ls [ pool-name ]

Will list all rbd images listed in the rbd_directory object.

info [ image-name ]

Will dump information (such as size and order) about a specific rbd image.

create [ image-name ]

Will create a new rbd image. You must also specify the size via --size.

resize [ image-name ]

Resizes rbd image. The size parameter also needs to be specified.

rm [ image-name ]

Deletes rbd image (including all data blocks)

rm [ image-name ]

Deletes rbd image (including all data blocks)

export [ image-name ] [ dest-path ]

Exports image to dest path.

import [ path ] [ dest-image ]

Creates a new image and imports its data from path.

cp [ src-image ] [ dest-image ]

Copies the content of a src-image into the newly created dest-image.

mv [ src-image ] [ dest-image ]

Renames an image.

snap ls [ image-name ]

Dumps the list of snapshots inside a specific image.

snap create [ image-name ]

Creates a new snapshot. Requires the snapshot name parameter specified.

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.

snap rm [ image-name ]

Removes the specified snapshot.

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

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

ceph(8),rados(8)