Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

308 Administering volume snapshots
Creating multiple snapshots
Figure 9-8 Splitting snapshots
Creating multiple snapshots
To make it easier to create snapshots of several volumes at the same time, both the
vxsnap make and vxassist snapshot commands accept more than one volume name
as their argument.
For traditional snapshots, you can create snapshots of all the volumes in a single disk
group by specifying the option -o allvols to the
vxassist snapshot command.
By default, each replica volume is named SNAPnumber-volume, where number is a
unique serial number, and volume is the name of the volume for which a snapshot is being
taken. This default can be overridden by using the option
-o name=pattern, as described
on the
vxsnap(1M) and vxassist(1M) manual pages.
It is also possible to take several snapshots of the same volume. A new FastResync change
map is produced for each snapshot taken to minimize the resynchronization time for each
snapshot.
Restoring the original volume from a snapshot
For traditional snapshots, the snapshot plex is resynchronized from the data in the original
volume during a vxassist snapback operation. Alternatively, you can choose the
snapshot plex as the preferred copy of the data when performing a snapback as illustrated
in Figure 9-9. Specifying the option -o resyncfromreplica to
vxassist
resynchronizes the original volume from the data in the snapshot.
vxsnap split S1
Original
volume
V
Snapshot
volume of V:
S1
Snapshot
volume of S1:
S2
Original
volume
V
Volume
S1
Snapshot
volume of S1:
S2
S1 is independent S2 continues to be a
snapshot of S1