VERITAS Volume Manager 3.5 Administrator's Guide (September 2004)

Creating Volumes

Creating a Mirrored Volume

Chapter 7 231

number. It is recommended that you conﬁgure as many DCO plexes as

there are data plexes in the volume. For example, specify ndcomirror=3

when creating a 3-way mirrored volume.

The default size of each plex is 132 blocks unless you use the dcolen

attribute to specify a different size. If speciﬁed, the size of the plex must

be a multiple of 33 blocks from 33 up to a maximum of 2112 blocks.

By default, FastResync is not enabled on newly created volumes. Specify

the fastresync=on attribute if you want to also enable FastResync on the

volume. If a DCO object and DCO volume are associated with the

volume, Persistent FastResync is enabled; otherwise, Non-Persistent

FastResync is enabled.

For more information about conﬁguring DCO, see the vxassist(1M)

manual page.

Creating a Mirrored Volume with DRL Logging

Enabled

To create a mirrored volume with dirty region logging (DRL) enabled,

use this command:

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

logtype=drl

NOTE By default, the vxassist command creates one log plex for a mirrored

volume.

For a volume that will be written to sequentially, such as a database log

volume, use the following command to specify that sequential DRL is to

be used:

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

logtype=drlseq

To add DRL logging to a volume that has DCO enabled, or to change the

number of DRL logs, follow the procedure that is described in “Adding

DRL Logging to a Mirrored Volume” on page 269.