Veritas Storage Foundation 5.1 SP1 Advanced Features Administrator"s Guide (5900-1503, April 2011)

# vxsnap -g mydg prepare vset2
# vxsnap -g mydg addmir vset2 nmirror=1
# vxsnap -g mydg make source=vset2/newvol=snapvset2/nmirror=1
See “Adding snapshot mirrors to a volume” on page 231.
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.
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.
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.
231Administering volume snapshots
Creating instant snapshots