VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Backing up Volumes Online
218 VERITAS Volume Manager Administrator’s Guide
Backing Up Multiple Volumes Using Snapshots
To make it easier to create snapshots of several volumes at the same time, the snapshot
option accepts more than one volume name as its argument, for example:
# vxassist [-g diskgroup] snapshot volume1 volume2 ...
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 the snapshot is
beingtaken. Thisdefaultpattern can beoverriddenby using theoption-o name=pattern,
as described on the vxassist(1M) manual page. For example, the pattern SNAP%v-%d
reverses the order of the number and volume components in the name.
To snapshot all the volumes in a single disk group, specify the option -o allvols to
vxassist:
# vxassist -g diskgroup -o allvols snapshot
This operation requires that all snapstart operations are complete on the volumes. It
fails if any of the volumes in the disk group do not have a complete snapshot plex in the
SNAPDONE state.
Merging a Snapshot Volume (snapback)
Note The information in this section does not apply to RAID-5 volumes unless they have
been converted to a special layered volume layout by the addition of a DCO and
DCO volume. See “Attaching a DCO and DCO volume to a RAID-5 Volume” on
page 195 for details.
Snapback merges a snapshot copy of a volume with the original volume. One or more
snapshot plexes are detached from the snapshot volume and re-attached to the original
volume. Thesnapshot volume is removedif all its snapshot plexesare snapped back. This
task resynchronizes the data in the volume so that the plexes are consistent.
Note To enhance the efficiency of the snapback operation, enable FastResync on the
volume before taking the snapshot, as described in “Enabling FastResync on a
Volume” on page 207.
To merge one snapshot plex with the original volume, use the following command:
# vxassist snapback snapshot
where snapshot is the snapshot copy of the volume.
To merge all snapshot plexes in the snapshot volume with the original volume, use the
following command:
# vxassist -o allplexes snapback snapshot