Snapshots are less costly than backing up your data on a separate physical storage device in terms of both time and storage consumption. The time required to move data to another physical device depends on the amount of data being moved, whereas snapshots are always created almost instantaneously regardless of the amount of data referenced by the snapshot. Also, because snapshots are available locally, end-users can often restore their data without requiring assistance from a system administrator. Snapshots require less space than a remote backup because unaltered data is referenced rather than recreated.
Snapshots do not protect against hardware or file-system issues. Snapshots reference data that is stored on a cluster, so if the data on the cluster becomes unavailable, the snapshots will also be unavailable. Because of this, it is recommended that you back up your data to separate physical devices in addition to creating snapshots.