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Part II. Snapshots
A snapshot is a read-only copy of the state of an image at a particular point in time. One of the advanced features of Ceph block devices is that you can create snapshots of the images to retain a history of an image’s state. Ceph also supports snapshot layering, which allows you to clone images (e.g. a VM image) quickly and easily. Ceph supports block device snapshots using the rbd command and many higher level interfaces, including QEMU, libvirt,OpenStack and CloudStack.
Important
To use RBD snapshots, you must have a running Ceph cluster.
Note
STOP I/O BEFORE taking a snapshot of an image. If the image contains a filesystem, the filesystem must be in a consistent state BEFORE taking a snapshot.
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