HP Veritas Volume Manager 5.0 -UX 11i v3 manual Adding plexes to a snapshot volume

Administering volume snapshots

Creating traditional third-mirror break-off snapshots

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plexes are snapped back. This task resynchronizes the data in the volume so that the plexes are consistent.

Note: To enhance the efficiency of the snapback operation, enable FastResync on the volume before taking the snapshot, as described in “Enabling FastResync on a volume” on page 292.

To merge one snapshot plex with the original volume, use the following command:

#vxassist [-g diskgroup] snapback snapshot where snapshot is the snapshot copy of the volume.

To merge all snapshot plexes in the snapshot volume with the original volume, use the following command:

#vxassist [-g diskgroup] -o allplexes snapback snapshot

To merge a specified number of plexes from the snapshot volume with the original volume, use the following command:

#vxassist [-g diskgroup] snapback nmirror=number snapshot

Here the nmirror attribute specifies the number of mirrors in the snapshot volume that are to be re-attached.

Once the snapshot plexes have been reattached and their data resynchronized, they are ready to be used in another snapshot operation.

By default, the data in the original volume is used to update the snapshot plexes that have been re-attached. To copy the data from the replica volume instead, use the following command:

#vxassist [-g diskgroup] -o resyncfromreplica snapback snapshot

Caution: Always unmount the snapshot volume (if mounted) before performing a snapback. In addition, you must unmount the file system corresponding to the primary volume before using the resyncfromreplica option.

Adding plexes to a snapshot volume

If you want to retain the existing plexes in a snapshot volume after a snapback operation, you can create additional snapshot plexes that are to be used for the snapback.

To add plexes to a snapshot volume

1Use 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‘