VERITAS Volume Manager 4.1 Administrator's Guide

Creating and Administering Disk Groups

Reorganizing the Contents of Disk Groups

Chapter 4 177

• In a cluster environment, disk groups involved in a move or join

must both be private or must both be shared.

The following sections describe how to use the vxdg command to

reorganize disk groups. For more information about the vxdg command,

see the vxdg(1M) manual page.

Listing Objects Potentially Affected by a Move

To display the VxVM objects that would be moved for a speciﬁed list of

objects, use the following command:

# vxdg [-o expand] listmove sourcedg targetdg object ...

The following example lists the objects that would be affected by moving

volume vol1 from disk group dg1 to rootdg:

# vxdg listmove dg1 rootdg vol1 disk01 c0t1d0 disk05 c1t96d0

vol1 vol1-01 vol1-02 disk01-01 disk05-01

However, the following command produces an error because only part of

the volume vol1 is conﬁgured on disk01:

# vxdg listmove dg1 rootdg disk01

vxvm:vxdg: ERROR: vxdg listmove dg1 rootdg failed

vxvm:vxdg: ERROR: disk05 : Disk not moving, but subdisks on it

are

Specifying the -o expand option ensures that the list of objects

encompasses other disks (in this case, disk05) that contain subdisks from

vol1.

# vxdg -o expand listmove dg1 rootdg disk01 disk01

c0t1d0disk05 c1t96d0vol1 vol1-01 vol1-02 disk01-01 disk05-01

Considerations for Placing DCO Plexes

If you use the vxassist command or the VERITAS Enterprise

Administrator (VEA) to create a volume, or to enable Persistent

FastResync on a volume, the DCO plexes are automatically placed on the

same disks as the data plexes of the parent volume. When you move the

parent volume (such as a snapshot volume) to a different disk group, this

ensures that the DCO volume automatically accompanies it. If you use

the vxassist addlog, vxmake or vxdco commands to set up a DCO for a

volume, you must ensure that the disks that contain the plexes of the