VERITAS Volume Manager 4.1 Administrator's Guide

Configuring Off-Host Processing
Implementing Off-Host Processing Solutions
Chapter 11 387
Persistent FastResync and disk group split and join features of VxVM. It
is beyond the scope of this guide to describe how to configure a database
to use this procedure, or how to perform the backup itself.
To back up a volume in a private disk group, use the following procedure.
Step 1. Use the following command on the primary host to see if the volume is
associated with a data change object (DCO) and DCO volume that allow
Persistent FastResync to be used with the volume:
# vxprint -g volumedg -F%hasdcolog volume
This command returns on if there is a DCO and DCO volume; otherwise,
it returns off.
If the volume is not associated with a DCO object and DCO volume,
follow the procedure described in “Adding a DCO and DCO Volume” on
page 277.
Step 2. Use the following command on the primary host to check whether
FastResync is enabled on a volume:
# vxprint -g volumedg -F%fastresync volume
This command returns on if FastResync is enabled; otherwise, it returns
off.
If Persistent FastResync is disabled, enable it using the following
command on the primary host:
# vxvol -g volumedg set fastresync=on volume
NOTE If the volume was created before release 3.2 of VxVM, and it has any
attached snapshot plexes or it is associated with any snapshot volumes,
follow the procedure given in “Enabling Persistent FastResync on
Existing Volumes with Associated Snapshots” on page 302.
Step 3. If the volume does not already contain a snapshot plex, create a snapshot
mirror for a volume using the following command on the primary host:
# vxassist -g volumedg [-b] snapstart [nmirror= N ] volume
The vxassist snapstart task creates a write-only mirror, which is
attached to and synchronized from the volume to be backed up.