VERITAS Volume Manager 4.1 Administrator's Guide

Administering Volumes

Adding a DCO and DCO Volume

Chapter 8 277

Adding a DCO and DCO Volume

CAUTION If the existing 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. The

procedure given in this section is for existing volumes without existing

snapshot plexes or associated snapshot volumes.

To put Persistent FastResync into effect for a volume, a Data Change

Object (DCO) and DCO volume must ﬁrst be associated with that

volume. When you have added a DCO object and DCO volume to a

volume, you can then enable Persistent FastResync on the volume as

described in “Enabling FastResync on a Volume” on page 298.

NOTE You may need an additional license to use the Persistent FastResync

feature. Even if you do not have a license, you can conﬁgure a DCO object

and DCO volume so that snap objects are associated with the original

and snapshot volumes. For more information about snap objects, see

“How Persistent FastResync Works with Snapshots” on page 54.

To add a DCO object and DCO volume to an existing volume (which may

already have dirty region logging (DRL) enabled), use the following

procedure:

Step 1. Ensure that the disk group containing the existing volume has been

upgraded to at least version 90. Use the following command to check the

version of a disk group:

# vxdg list diskgroup

To upgrade a disk group to the latest version, use the following

command:

# vxdg upgrade diskgroup

For more information, see “Upgrading a Disk Group” on page 190.