Snapshots are read only, point-in-time images of a volume. They are created once and cannot be changed. They can be attached to hosts as read only block devices.

Clones are simply new volumes which start as copies of the snapshot. Volumes and snapshots share the same name space, thus their names are unique within a StorPool cluster. Volumes can be based on snapshots. Such volumes contain only the changes since the snapshot was taken.

After a volume is created from a snapshot, writes will be recorded within the volume. Reads from the volume may be served by the volume, or by its parent snapshot, depending on whether the volume contains changed data for the read request or not. Thus you can make significant savings on the space used, if you have a snapshot as a base image and then make a lot of new volumes / virtual machines from this snapshot (i.e. template).

Snapshots are also used for backups, Disaster Recovery (DR). This is implemented by creating a snapshot of a volume at regular intervals and sending these snapshots to a remote site. In order to save space and reduce time of the process only the differences since last state are copied, not the whole volume again and again.

• Increased reliability
• Easier infrastructure management
• Quicker deployments

Technical Benefits

• Easier backups
• Faster instantiation of new virtual machines
• More efficient space usage