Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

See “Adding snapshot mirrors to a volume” on page 383.
To create a space-optimized instant snapshot of a volume set, the commands are
again identical to those for a standalone volume as shown in these examples:
# vxsnap -g mydg prepare vset3
# vxsnap -g mydg make source=vset3/newvol=snapvset3/cachesize=20m
# vxsnap -g mydg prepare vset4
# vxsnap -g mydg make source=vset4/newvol=snapvset4/cache=mycobj
Here a new cache object is created for the volume set, vset3, and an existing cache
object, mycobj, is used for vset4.
See “About volume sets” on page 411.
Adding snapshot mirrors to a volume
If you are going to create a full-sized break-off snapshot volume, you can use the
following command to add new snapshot mirrors to a volume:
# vxsnap [-b] [-g diskgroup] addmir volume|volume_set \
[nmirror=N] [alloc=storage_attributes]
The volume must have been prepared using the vxsnap prepare command.
See “Preparing a volume for DRL and instant snapshots” on page 318.
If a volume set name is specified instead of a volume, the specified number of
plexes is added to each volume in the volume set.
By default, the vxsnap addmir command adds one snapshot mirror to a volume
unless you use the nmirror attribute to specify a different number of mirrors.
The mirrors remain in the SNAPATT state until they are fully synchronized. The
-b option can be used to perform the synchronization in the background. Once
synchronized, the mirrors are placed in the SNAPDONE state.
For example, the following command adds 2 mirrors to the volume, vol1, on disks
mydg10 and mydg11:
# vxsnap -g mydg addmir vol1 nmirror=2 alloc=mydg10,mydg11
This command is similar in usage to the vxassist snapstart command, and
supports the traditional third-mirror break-off snapshot model. As such, it does
not provide an instant snapshot capability.
383Administering volume snapshots
Creating instant snapshots