VERITAS Volume Manager 4.1 Administrator's Guide

Creating Volumes

Creating a Mirrored Volume

Chapter 7244

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.

Dirty region logging (DRL) is the default log type if you specify the log

attribute to enable logging on a mirrored volume, but do not use the

logtype attribute to specify the type of logging to vxassist.

NOTE Only one type of logging may initially be speciﬁed when you use vxassist

to create a volume.

To create a volume with an attached DCO object and DCO volume, use

the following procedure:

Step 1. Ensure that the disk group 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.

Step 2. Use the following command to create the volume (you may need to

specify additional attributes to create a volume with the desired

characteristics):

# vxassist [-g diskgroup] make volume length layout=layout

logtype=dco [ndcomirror=number] [dcolen=size]

[fastresync=on]

For non-layered volumes, the default number of plexes in the mirrored

DCO volume is equal to the lesser of the number of plexes in the data

volume or 2. For layered volumes, the default number of DCO plexes is

always 2. If required, use the ndcomirror attribute to specify a different