Veritas FlashSnap Point-In-Time Copy Solutions 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

22 Setting up volumes for instant snapshots
Additional preparation activities
Caution: To avoid data inconsistencies, do not use the same snapshot with
different point-in-time copy applications. If you require snapshot mirrors for
more than one application, configure at least one snapshot mirror that is
dedicated to each application.
If the existing volume was created before release 4.0 of VxVM, and it has any
attached snapshot plexes, is associated with any snapshot volumes, or has any
dedicated DRL logs, follow the procedure given in the section “Upgrading
Existing Volumes to Use Version 20 DCOs” in the “Administering Volumes”
chapter of the Veritas Volume Manager Administrator’s Guide. The procedure
given in this section assumes that no snapshot plexes, snapshot volumes, or
DRL logs are associated with the volumes.
Additional preparation activities
Depending on the type of snapshots that you want to create, you may need to
perform additional preparatory tasks.
When creating a full-sized instant snapshot, you can use one of the following
two methods:
■ Break off one or more spare plexes from the original volume to form a
snapshot volume with the required redundancy. These plexes must be in the
SNAPDONE state. (You can also break off named plexes of a volume that are
in the ACTIVE state, but that method is not described here. For more
information, see the “Administering Volume Snapshots” chapter in the
Veritas Volume Manager Administrator’s Guide.)
■ Use a separate empty volume that you have prepared in advance as
described in “Creating a volume for use as a full-sized instant snapshot” on
page 27.
When creating space-optimized instant snapshots that share a cache, you must
set up the cache before creating the snapshots. See “Creating a shared cache
object” on page 28 for details.
If a space-optimized instant snapshot uses a dedicate cache, this can also be set
up when the snapshot is created. No additional preparation is required in this
case.
Note: The off-host processing solutions in this book require full-sized
snapshots.