Veritas Volume Manager 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Implementing Off-Host Processing Solutions
320 VERITAS Volume Manager Administrator’s Guide
placed on disks which are used to hold the plexes of other volumes, this may
cause problems when you subsequently attempt to move a snapshot volume
into another disk group as described in “Moving DCO Volumes Between Disk
Groups” on page 161. To override the default storage allocation policy, you can
use storage attributes to specify explicitly which disks to use for the snapshot
plexes. See “Creating a Volume on Specific Disks” on page 203 for more
information.
If a database spans more than one volume, you can specify all the volumes and their
snapshot volumes using one command, as shown in this example:
# vxsnap -g dbasedg make source=vol1/newvol=snapvol1/nmirror=1 \
source=vol2/newvol=snapvol2/nmirror=1 \
source=vol3/newvol=snapvol3/nmirror=1
Note This step sets up the snapshot volumes ready for the backup cycle, and starts
tracking changes to the original volumes. When you are ready to make a
backup, proceed to step 5.
5. On the primary host, suspend updates to the volume that contains the database
tables. The database may have a hot backup mode that allows you to do this by
temporarily suspending writes to its tables.
6. On the primary host, refresh the plexes of the snapshot volume using the following
command:
# vxsnap [-g diskgroup] refresh snapvol source=volume syncing=yes
For a database, multiple snapshots can be refreshed in parallel, as shown in this
example:
# vxsnap -g dbasedg refresh snapvol1 source=vol1 snapvol2 \
source=vol2 snapvol3 source=vol3 syncing=yes
7. On the primary host, if you temporarily suspended updates to the volume by a
database in step 5, release all the tables from hot backup mode.
8. The snapshot volume must be completely synchronized before you can move it into
another disk group. You can use the vxsnap syncwait command to wait for the
synchronization to complete as shown here:
# vxsnap -g volumedg syncwait snapvol
The vxsnap syncwait command exits with an exit code of zero when the snapshot
volume has been synchronized with the parent volume.