VERITAS Volume Manager 4.1 Administrator's Guide

Creating Volumes
Creating a Mirrored Volume
Chapter 7 243
NOTE Specify the -b option if you want to make the volume immediately
available for use. See “Initializing and Starting a Volume” on page 258
for details.
Alternatively, first create a concatenated volume, and then mirror it as
described in “Adding a Mirror to a Volume” on page 273.
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 258
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 54 for
details of how Persistent FastResync performs fast resynchronization of
snapshot mirrors when they are returned to their original volume.)
To perform fast resynchronization of mirrors after a system crash or
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 277.