VERITAS Storage Foundation 4.1 Intelligent Storage Provisioning Administrator's Guide

Chapter 4, Administering Application Volumes

Performing Online Relayout on a Volume

ISP does not support online relayout of an application volume in the same way as when the

vxassist relayout command is used on a traditional volume. ISP can perform relayout

internally if this is necessary to preserve the intent of a volume, or to support operations such as

changing the number of mirrors, columns or logs that are associated with a volume. However, you

should note that such operations may destroy the intent of a volume by changing its desired data

redundancy or performance capabilities.

The nearest equivalent in ISP to the online relayout operation is capability transformation. This

changes the capabilities of a volume in a controlled fashion, and preserves the size of the volume

but not its intent. This operation is discussed in the following section. Subsequent sections describe

how to add or remove mirrors, columns or logs to or from a volume, how to stop and reverse

transformation and relayout operations, and how to verify that the intent of a volume has been

preserved.

Transforming the Capabilities of a Volume Online

To change the capabilities of an existing volume online, use the vxvoladm transform

command as shown here:

# vxvoladm [-g diskgroup] [-b] transform volume [attributes...]

If specified, the -b option performs the transformation in the background.

For example, the following command changes the capability of the volume, vol02, to

DataMirroring with 4 mirrors:

# vxvoladm -g mydg -b transform vol02 \

capability=’DataMirroring (nmirs=4)’

The next example adds the InstantSnapShottable and DCOLogMirroring capabilities to enable the

use of instant snapshots with a mirrored volume:

# vxvoladm -g mydg -b transform mir3vol \

capability=’DataMirroring(nmirs=3),InstantSnapShottable,\

DCOLogMirroring(nlogs=3)’