Veritas FlashSnap Point-In-Time Copy Solutions 5.0.1 Administrators Guide, HP-UX 11i v3, First Edition, November 2009

■ If redundancy is a desired characteristic of the cache volume, it should
be mirrored. This increases the space that is required for the cache volume
in proportion to the number of mirrors that it has.
■ If the cache volume is mirrored, space is required on at least as many disks
as it has mirrors. These disks should not be shared with the disks used
for the parent volumes. The disks should also be chosen to avoid impacting
I/O performance for critical volumes, or hindering disk group split and
join operations.
2
Having decided on its characteristics, use the vxassist command to create
the volume that is to be used for the cache volume. The following example
creates a mirrored cache volume, cachevol, with size 1GB in the disk group,
mydg, on the disks mydg16 and mydg17:
# vxassist -g mydg make cachevol 1g layout=mirror \
init=active mydg16 mydg17
The attribute init=active is specified to make the cache volume immediately
available for use.
37Setting up volumes for instant snapshots
Creating a shared cache object