Veritas Storage Foundation Intelligent Storage Provisioning 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

Chapter
5
Administering instant
snapshots
Veritas Volume Manager (VxVM) provides the capability for taking an image of a
volume at a given point in time. Such an image is referred to as a volume
snapshot.
Instant volume snapshots allow you to make backup copies of your volumes
online with minimal interruption to users. You can then use the backup copies
to restore data that has been lost due to disk failure, software errors or human
mistakes, or to create replica volumes for the purposes of report generation,
application development, or testing.
Three kinds of instant volume snapshots are supported for use with application
volumes created by Veritas Intelligent Storage Provisioning (ISP):
■ Full-sized instant snapshots require an empty volume to be prepared for use
as the snapshot volume. The length of this volume must be the same as that
of the volume whose snapshot is being taken. A snapshot volume can be
created in either a data pool or in a clone pool.
■ Linked break-off snapshot volumes differ from full-sized instant snapshots
in that they can be set up in a different disk group from the data volume.
This makes them especially suitable for off-host processing applications
where you may want to create the snapshot on storage with different
characteristics from that used for the data volumes.
■ Space-optimized instant snapshots require less space than a full-sized
instant snapshot but they cannot be dissociated from their original volume
nor can they be moved into a different disk group. A space-optimized
snapshot uses a storage pool or cache, which can be shared by one or more
other space-optimized snapshots. You must set up the cache and the space-
optimized snapshot volume in advance of creating any space-optimized
snapshots.