VERITAS FlashSnap Point-In-Time-Copy Solutions Administrator's Guide

Using Off-Host Processing to Back Up Cluster File Systems
44 VERITAS FlashSnap Point-In-Time Copy Solutions Administrator’s Guide
14. When the backup is complete, use the following command to unmount the snapshot volume,
and make it ready for its contents to be refreshed from the primary volume:
# umount mount_point
When synchronization is complete, the snapshot is ready to be re-used for backup.
Caution Before attempting to unmount the snapshot, shut down all applications that access a file
system in the snapshot volume, and also unmount any such file system.
Repeat steps 2 through 14 each time that you need to back up the volume.
In some instances, such as recovering the contents of a corrupted volume, it may be useful to
resynchronize a volume from its snapshot volume (which is used as a hot standby):
# vxsnap -g diskgroup restore volume source=snapvol destroy=yes|no
The destroy attribute specifies whether the plexes of the snapshot volume are to be reattached to
the original volume. For example, to resynchronize the volume cfs_vol from its snapshot
volume scfs_vol:
# vxsnap -g exampledg restore cfs_vol source=scfs_vol destroy=no
Note You must unmount the file system that is configured on the original volume before
attempting to resynchronize its contents from a snapshot.
Reattaching Snapshot Plexes
Note This operation is not supported for space-optimized instant snapshots.
Using the following command, some or all plexes of an instant snapshot may be reattached to the
specified original volume, or to a source volume in the snapshot hierarchy above the snapshot
volume:
# vxsnap [-g diskgroup] reattach snapvol source=vol \
[nmirror=number]
By default, all the plexes are reattached, which results in the removal of the snapshot. If required,
the number of plexes to be reattached may be specified as the value assigned to the nmirror
attribute.
Note The snapshot being reattached must not be open to any application. For example, any file
system configured on the snapshot volume must first be unmounted.
For example the following command reattaches 1 plex from the snapshot volume, snapmyvol, to
the volume, myvol:
# vxsnap -g mydg reattach snapmyvol source=myvol nmirror=1