VERITAS Volume Manager 3.1 Administrator's Guide

Volume Tasks
Mirroring a Volume
Chapter 6248
Mirroring a Volume
NOTE You may need an additional license to use this feature.
A mirror is a copy of a volume. The mirror copy is not stored on the same
disk(s) as the original copy of the volume. Mirroring a volume ensures
that the data in that volume is not lost if one of your disks fails.
NOTE To mirror the root disk, use vxrootmir (1M). See the manual page for
details.
Creating a Volume with Dirty Region Logging
Enabled
To create a mirrored volume with Dirty Region Logging (DRL) enabled,
create a mirrored volume with a log with this command:
# vxassist make volume_name length layout=mirror,log
The vxassist command creates one log plex for each log subdisk, by
default.
Mirroring an Existing Volume
A mirror (plex) can be added to an existing volume with the vxassist
command, as follows:
# vxassist mirror volume_name
For example, to create a mirror of the volume voltest, use the following
command:
# vxassist mirror voltest
Another way to mirror an existing volume is by first creating a plex and
then associating it with a volume, using the following commands:
# vxmake plex plex_name sd= subdisk_name ...