VERITAS Volume Manager 4.1 Administrator's Guide

Administering Volumes
Backing up Volumes Online
Chapter 8312
Step 5. Use a backup utility or operating system command to copy the
temporary volume to tape, or to some other appropriate backup media.
When the backup is complete, you have three choices for what to do with
the snapshot volume:
• Reattach some or all of the plexes of the snapshot volume with the
original volume as described in “Merging a Snapshot Volume
(snapback)” on page 314. If FastResync was enabled on the volume
before the snapshot was taken, this speeds resynchronization of the
snapshot plexes before the backup cycle starts again at step 3.
• Dissociate the snapshot volume entirely from the original volume as
described in “Dissociating a Snapshot Volume (snapclear)” on
page 315. This may be useful if you want to use the copy for other
purposes such as testing or report generation.
• Remove the snapshot volume to save space with this command:
# vxedit [-g diskgroup] -rf rm snapshot
NOTE Dissociating or removing the snapshot volume loses the advantage of
fast resynchronization if FastResync was enabled. If there are no
further snapshot plexes available, any subsequent snapshots that
you take require another complete copy of the original volume to be
made.
Converting a Plex into a Snapshot Plex
In some circumstances, you may find it more convenient to convert an
existing plex in a volume into a snapshot plex rather than running
vxassist snapstart. For example, you may want to do this if you are short
of disk space for creating the snapshot plex and the volume that you
want to snapshot contains more than two plexes.
NOTE It is advisable to retain at least two plexes in a volume to maintain data
redundancy.
To convert an existing plex into a snapshot plex for a volume on which
Persistent FastResync is enabled, use the following command: