VERITAS Volume Manager 3.5 Administrator's Guide (September 2004)

Configuring Off-Host Processing
Implementing Off-Host Processing Solutions
Chapter 11378
Use the nmirror attribute to create as many snapshot mirrors as you
need for the snapshot volume. For a backup, you should usually only
require the default of one.
Step 4. If the volume to be backed up contains database tables in a file system,
suspend updates to the volume. The database may have a hot backup
mode that allows you to do this by temporarily suspending writes to its
tables.
Step 5. On the primary host, make a snapshot volume, snapvol, using the
following command:
# vxassist -g volumedg snapshot [nmirrors= N ] volume snapvol
If required, use the nmirrors attribute to specify the number of mirrors
in the snapshot volume.
If a database spans more than one volume, specify all the volumes and
their snapshot volumes on the same line, for example:
# vxassist -g dbasedg snapshot vol1 snapvol1 vol2 snapvol2 \
vol3 snapvol3
Step 6. If you temporarily suspended updates to the volume by a database in
step 4, release all the tables from hot backup mode.
Step 7. On the primary host, use the following command to split the snapshot
volume into a separate disk group, snapvoldg, from the original disk
group, volumedg:
# vxdg split volumedg snapvoldg snapvol
Step 8. On the primary host, deport the snapshot volume’s disk group using the
following command:
# vxdg deport snapvoldg
Step 9. On the OHP host where the backup is to be performed, use the following
command to import the snapshot volume’s disk group:
# vxdg import snapvoldg
Step 10. The snapshot volume is initially disabled following the split. Use the
following commands on the OHP host to recover and restart the snapshot
volume:
# vxrecover -g snapvoldg -m snapvol