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

Chapter 9, Administering Volume Snapshots
Creating Traditional Third-Mirror Break-Off Snapshots
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Adding Plexes to a Snapshot Volume
If you want to retain the existing plexes in a snapshot volume after a snapback operation,
create additional snapshot plexes that are to be used for the snapback:
1. Use the following vxprint commands to discover the names of the snapshot
volume’s data change object (DCO) and DCO volume:
# DCONAME=‘vxprint [-g diskgroup] -F%dco_name snapshot‘
# DCOVOL=‘vxprint [-g diskgroup] -F%log_vol $DCONAME‘
2. Use the vxassist mirror command to create mirrors of the existing snapshot
volume and its DCO volume:
# vxassist -g diskgroup mirror snapshot
# vxassist -g diskgroup mirror $DCOVOL
Note The new plex in the DCO volume is required for use with the new data plex in
the snapshot.
3. Use the vxprint command to find out the name of the additional snapshot plex:
# vxprint -g diskgroup snapshot
4. Use the vxprint command to find out the record ID of the additional DCO plex:
# vxprint -g diskgroup -F%rid $DCOVOL
5. Use the vxedit command to set the dco_plex_rid field of the new data plex to the
name of the new DCO plex:
# vxedit -g diskgroup set dco_plex_rid=dco_plex_rid new_plex
The new data plex is now ready to be used to perform a snapback operation.
Dissociating a Snapshot Volume (vxassist snapclear)
The link between a snapshot and its original volume can be permanently broken so that
the snapshot volume becomes an independent volume. Use the following command to
dissociate the snapshot volume, snapshot:
# vxassist snapclear snapshot