Using snapshots and clones, you can make point-in-time copies of a share or project. These copies can be useful as backups or as different working versions.
A snapshot is a read-only copy of a filesystem, LUN, or project. Taking a project snapshot is equivalent to snapshotting all of the shares in the project. A snapshot takes up no additional space when it is first created, but as the active share changes, the snapshot takes up additional space, with a maximum equivalent to the size of the share at the time the snapshot was taken.
A clone is a writable copy of a filesystem or LUN snapshot and can be treated as an independent share. Clones of projects are not supported. Like a snapshot, a clone consumes no additional space when it is first created, but as new data is written to the clone, the space required for the changes are associated with the clone.
You can take snapshots manually, or you can set a schedule so that snapshots are taken automatically every half-hour, hour, day, week, or month. Some snapshots are taken by the appliance automatically during replication updates; these will appear on the snapshot page with .ndmp and .rr in their names.
For information about snapshot space management, see the following:
To take manual snapshots or schedule automatic snapshots of projects or shares, use the following tasks:
You can make clones of a snapshot, which can be useful to create numerous working versions of one share. To make clones, use the following tasks:
To determine the relationships between existing snapshots and clones, use the following tasks:
To view and edit existing snapshots, snapshot schedules, and snapshot retention policies, use the following tasks:
You can look at the contents of filesystem snapshots through the .zfs/snapshot filesystem directory. LUN snapshots cannot be accessed directly, though they can be used as a rollback target or as the source of a clone. To manage and access the .zfs/snapshot directory, use the following tasks:
You can use an existing snapshot to restore a filesystem or LUN to the exact state it was in when the snapshot was taken. To roll back a filesystem, LUN, or project to an existing snapshot, use the following tasks:
To destroy snapshots, use the following tasks: