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

Chapter 8, Administering Volumes

Adding a Mirror to a Volume

191

Adding a Mirror to a Volume

A mirror can be added to an existing volume with the vxassist command, as follows:

# vxassist [-b] [-g diskgroup] mirror volume

Note If speciﬁed, the -b option makes synchronizing the new mirror a background task.

For example, to create a mirror of the volume voltest, use the following command:

# vxassist -b mirror voltest

Another way to mirror an existing volume is by ﬁrst creating a plex, and then attaching it

to a volume, using the following commands:

# vxmake plex plex sd=subdisk ...

# vxplex att volume plex

Mirroring All Volumes

To mirror all volumes in a diskgroupto availabledisk space,use thefollowing command:

# /etc/vx/bin/vxmirror -g diskgroup -a

To conﬁgure VxVM to create mirrored volumes by default, use the following command:

# /etc/vx/bin/vxmirror -d yes

If you make this change, you can still make unmirrored volumes by specifying

nmirror=1 as an attribute to the vxassist command. For example, to create an

unmirrored 20-gigabyte volume named nomirror, use the following command:

# vxassist make nomirror 20g nmirror=1

Mirroring Volumes on a VM Disk

Mirroring volumes on a VM disk gives you one or more copies of your volumes in

another disk location.By creatingmirror copies of your volumes, you protectyour system

against loss of data in case of a disk failure.

Note This task only mirrors concatenated volumes. Volumes that are already mirrored or

that contain subdisks that reside on multiple disks are ignored.