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

Chapter 8, Administering Volumes

Backing up Volumes Online

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To merge a speciﬁed number of plexes from the snapshot volume with the original

volume, use the following command:

# vxassist snapback nmirror=number snapshot

Here the nmirror attribute speciﬁes the number of mirrors in the snapshot volume that

are to be re-attached.

Once the snapshot plexes have been reattached and their data resynchronized, they are

ready to be used in another snapshot operation.

By default, the datain theoriginal volumeis usedto updatethe snapshotplexes thathave

been re-attached. To copy the data from the replica volume instead, use the following

command:

# vxassist -o resyncfromreplica snapback snapshot

Caution Unmount the ﬁle system correspondingto theprimary volumebeforeusing the

resyncfromreplica option.

Dissociating a Snapshot Volume (snapclear)

The link between a snapshot and its original volume can be permanently broken so that

the snapshot volume becomes an independent volume.

If Non-Persistent FastResync is enabled on the original volume, use the following

command to dissociate the snapshot volume, snapshot:

# vxassist snapclear snapshot

If Persistent FastResync is enabled, and both the snapshot volume and the original

volume are still in the same disk group, use either of the following commands to stop

FastResync tracking on both volumes with respect to each other:

# vxassist snapclear volume snap_object1

# vxassist snapclear snapshot snap_object2

Here snap_object1 is the snap object in the original volume that refers to the snapshot

volume, and snap_object2 is the snap object in the snapshot volume that refers to the

original volume. For example, if myvol and SNAP-myvol are in the same disk group

mydg, either of the following commands stops tracking for both myvol and SNAP-myvol:

# vxassist -g mydg snapclear SNAP-myvol myvol_snp

# vxassist -g mydg snapclear myvol SNAP-myvol_snp

If you have split or moved the snapshot volume and the original volume into different

disk groups, you must run snapclear on the each volume separately, specifying the

snap object in the volume that points to the other volume:

# vxassist snapclear volume snap_object