Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

263Administering volumes

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 in the disk group, mydg, use the

following command:

# vxassist -b -g mydg 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 [-g diskgroup] plex plex sd=subdisk ...

# vxplex [-g diskgroup] att volume plex

Mirroring all volumes

To mirror all volumes in a disk group to available disk space, use the following 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 in the disk group, mydg, use the

following command:

# vxassist -g mydg 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 creating mirror copies of your volumes, you protect your 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.

To mirror volumes on a disk

1 Make sure that the target disk has an equal or greater amount of space as the

originating disk.