Veritas Storage Foundation 5.1 SP1 Advanced Features Administrator"s Guide (5900-1503, April 2011)

Create a snapshot volume using the following command:

# vxassist [-g diskgroup] snapshot [nmirror=N] volume snapshot

If required, use the nmirror attribute to specify the number of mirrors in the

snapshot volume.

For example, to create a snapshot of voldef, use the following command:

# vxassist -g mydg snapshot voldef snapvoldef

The vxassist snapshot task detaches the finished snapshot mirror, creates

a new volume, and attaches the snapshot mirror to it. This step should only

take a few minutes. The snapshot volume, which reflects the original volume

at the time of the snapshot, is now available for backing up, while the original

volume continues to be available for applications and users.

If required, you can make snapshot volumes for several volumes in a disk

group at the same time.

See “Creating multiple snapshots with the vxassist command” on page 249.

Use fsck (or some utility appropriate for the application running on the

volume) to clean the temporary volume’s contents.

For example, you can use this command with a VxFS file system:

# fsck -F vxfs /dev/vx/rdsk/diskgroup/snapshot

The specified device must have a valid entry in the /etc/fstab file.

If you require a backup of the data in the snapshot, use an appropriate utility

or operating system command to copy the contents of the snapshot to tape,

or to some other backup medium.

When the backup is complete, you have the following choices for what to do

with the snapshot volume:

■ Reattach some or all of the plexes of the snapshot volume with the original

volume.

See “Reattaching a snapshot volume” on page 250.

■ If FastResync was enabled on the volume before the snapshot was taken,

this speeds resynchronization of the snapshot plexes before the backup

cycle starts again at step 3.

■ Dissociate the snapshot volume entirely from the original volume

See “Dissociating a snapshot volume” on page 252.

■ This may be useful if you want to use the copy for other purposes such as

testing or report generation.

247Administering volume snapshots

Creating traditional third-mirror break-off snapshots