Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

Creating a volume for use as a full-sized instant or linked
break-off snapshot
To create an empty volume for use by a full-sized instant snapshot or a linked
break-off snapshot
1
Use the vxprint command on the original volume to find the required size
for the snapshot volume.
# LEN=`vxprint [-g diskgroup] -F%len volume`
The command as shown assumes a Bourne-type shell such as sh, ksh or bash.
You may need to modify the command for other shells such as csh or tcsh.
2
Use the vxprint command on the original volume to discover the name of
its DCO:
# DCONAME=`vxprint [-g diskgroup] -F%dco_name volume`
3
Use the vxprint command on the DCO to discover its region size (in blocks):
# RSZ=`vxprint [-g diskgroup] -F%regionsz $DCONAME`
4
Use the vxassist command to create a volume, snapvol, of the required size
and redundancy, together with a version 20 DCO volume with the correct
region size:
# vxassist [-g diskgroup] make snapvol $LEN \
[layout=mirror nmirror=number] logtype=dco drl=off \
dcoversion=20 [ndcomirror=number] regionsz=$RSZ \
init=active [storage_attributes]
Specify the same number of DCO mirrors (ndcomirror) as the number of
mirrors in the volume (nmirror). The init=active attribute makes the volume
available immediately. You can use storage attributes to specify which disks
should be used for the volume.
As an alternative to creating the snapshot volume and its DCO volume in a
single step, you can first create the volume, and then prepare it for instant
snapshot operations as shown here:
# vxassist [-g diskgroup] make snapvol $LEN \
[layout=mirror nmirror=number] init=active \
[storage_attributes]
# vxsnap [-g diskgroup] prepare snapvol [ndcomirs=number] \
regionsize=$RSZ [storage_attributes]
Administering volume snapshots
Creating instant snapshots
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