Storage Foundation Cluster File System High Availability 7.2 Administrator's Guide - Solaris

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 an instant snap 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]

   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]