To create an empty volume for use by a full-sized instant snapshot or a linked break-off snapshot
# 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.
# DCONAME='vxprint [-g diskgroup] -F%dco_name volume'
# RSZ='vxprint [-g diskgroup] -F%regionsz $DCONAME'
# vxassist [-g diskgroup] make snapvol $LEN \ [layout=mirror nmirror=number] logtype=dco drl=off \ dcoversion=20 [ndcomirror=number] regionsz=$RSZ \ init=active [storage_attributes]
Storage attributes give you control over the devices, including disks and controllers, which vxassist uses to configure a volume.
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]
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