HP XP P9000 Command View Advanced Edition Software - Manual (Page 460)

Snapshot Software used to duplicate volumes in a single storage system. Snapshot
duplicates differential data in a data pool. The secondary volume is a virtual
volume that consists of the primary volume and the differential data. By duplicating
only the differential data, Snapshot can copy data in a very short time as well
as reduce the capacity required of the volume used for duplication. For more
information, see the Snapshot manuals.
Glossary 460