VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Chapter 7, Creating Volumes

Creating a Mirrored Volume

171

Creating a Concatenated-Mirror Volume

Note You may need an additional license to use this feature.

A concatenated-mirror volume is an example of a layered volume which concatenates

several underlying mirror volumes. To create a concatenated-mirror volume, use the

following command:

# vxassist [-b] [-g diskgroup] make volume length \

layout=concat-mirror [nmirror=number]

Note Specify the -b option if you want to make the volume immediately available for

use. See “Initializing and Starting a Volume” on page 181 for details.

Creating a Volume with a DCO and DCO Volume

If a data change object (DCO) and DCO volume are associated with a volume, this allows

Persistent FastResync to be used with the volume. (See “How Persistent FastResync

Works with Snapshots” on page 45 for details of how Persistent FastResync performs fast

resynchronization of snapshot mirrors when they are returned to their original volume.)

To perform fastresynchronizationof mirrors after a system crashor reboot, you must also

enable dirty region logging (DRL) on a mirrored volume. To add a DCO object and DCO

volume to a volume on which DRL logging is enabled, follow the procedure described in

“Adding a DCO and DCO Volume” on page 193.

Note You mayneed an additional license touse the Persistent FastResyncfeature. Even if

you donot have a license, you can conﬁgure a DCOobject 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 45.

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.