About the copy-on-write snapshot type

A copy-on-write type of snapshot is a detailed account of data as it existed at a certain moment. A copy-on-write snapshot is not a copy of the data, but a specialized account of it.

A copy-on-write snapshot is created in the client's file system or in a raw partition. The copy-on-write is not created as a complete copy of the client data on a separate or a mirror disk. The snapshot is then backed up to storage as specified in the backup policy. Users can access their data without interruption, as though no backup is underway. The file system is paused long enough to assemble a transactionally consistent record.

See How copy-on-write works.

Note that VxFS allows two kinds of copy-on-write snapshots: file system snapshots and Storage Checkpoints.

See Benefits of copy-on-write versus mirror.

See About the mirror snapshot type.