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

Implementing Off-Host Processing Solutions
276 VERITAS Volume Manager Administrator’s Guide
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
6. If you temporarily suspended updates to the volume by a database in step 4, release
all the tables from hot backup mode.
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
8. On the primary host, deport the snapshot volume’s disk group using the following
command:
# vxdg deport snapvoldg
9. On the OHPhost wherethe backupis to beperformed, usethe following commandto
import the snapshot volume’s disk group:
# vxdg import snapvoldg
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
# vxvol -g snapvoldg start snapvol
11. On the OHP host, back up the snapshot volume. If you need to remount the file
system in the volume to back it up, first run fsck on the volume. The following are
sample commands for checking and mounting a file system:
# fsck -F vxfs /dev/vx/rdsk/snapvoldg/snapvol
# mount -F vxfs /dev/vx/dsk/snapvoldg/snapvol mount_point
Back up the file system at this point, and then use the following command to
unmount it.
# umount mount_point