VERITAS Volume Manager 3.1 Administrator's Guide

Volume Tasks
Performing Online Backup
Chapter 6288
also ask users to refrain from using the system during the brief time
required to perform the snapshot (typically less than a minute). The
amount of time involved in creating the snapshot mirror is long in
contrast to the brief amount of time that it takes to create the snapshot
volume.
The online backup procedure is completed by running the vxassist
snapshot command on a volume with a SNAPDONE mirror. This task
detaches the finished snapshot (which becomes a normal mirror),
creates a new normal volume and attaches the snapshot mirror to the
snapshot volume. The snapshot then becomes a normal, functioning
mirror and the state of the snapshot is set to ACTIVE.
If the snapshot procedure is interrupted, the snapshot mirror is
automatically removed when the volume is started.
Use the following steps to perform a complete vxassist backup:
Step 1. Create a snapshot mirror for a volume with this command:
# vxassist snapstart volume_name
Step 2. When the snapstart step is complete and the mirror is in a
SNAPDONE state, choose a convenient time to complete the snapshot
task. Inform users of the upcoming snapshot and ask them to save files
and refrain from using the system briefly during that time.
Create a snapshot volume that reflects the original volume with this
command:
# vxassist snapshot volume_name temp_volume_name
Step 3. Use fsck (or some utility appropriate for the application running on the
volume) to clean the temporary volume’s contents. For example, you can
use this command:
# fsck -y /dev/vx/rdsk/ temp_volume_name
Step 4. Copy the temporary volume to tape, or to some other appropriate backup
media.
Step 5. Remove the new volume with this command:
# vxedit -rf rm temp_volume_name