-====================
- RADOS RBD Commands
-====================
+==============
+ RBD Commands
+==============
+
The ``rbd`` command enables you to create, list, introspect and remove block
device images. You can also use it to clone images, create snapshots,
rollback an image to a snapshot, view a snapshot, etc. For details on using
.. important:: To use RBD commands, you must have a running Ceph cluster.
Creating a Block Device Image
------------------------------
+=============================
+
Before you can add a block device to a Ceph client, you must create an image for
it in the OSD cluster first. To create a block device image, execute the
following::
source. See `Storage Pools`_ for details.
Listing Block Device Images
----------------------------
+===========================
+
To list block devices in the ``rbd`` pool, execute the following::
rbd ls
rbd ls swimmingpool
Retrieving Image Information
-----------------------------
+============================
+
To retrieve information from a particular image, execute the following,
but replace ``{image-name}`` with the name for the image::
rbd --image bar -p swimmingpool info
Resizing a Block Device Image
------------------------------
+=============================
+
RBD images are thin provisioned. They don't actually use any physical storage
until you begin saving data to them. However, they do have a maximum capacity
that you set with the ``--size`` option. If you want to increase (or decrease)
Removing a Block Device Image
------------------------------
+=============================
+
To remove a block device, execute the following, but replace ``{image-name}``
with the name of the image you want to remove::