Veritas Volume Manager 5.0.1 Administrator's Guide, HP-UX 11i v3, First Edition, November 2009

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.
Warning: The snapshot that is being reattached must not be open to any
application. For example, any file system configured on the snapshot volume must
first be unmounted.
It is possible to reattach a volume to an unrelated volume provided that their
volume sizes and region sizes are compatible.
For example the following command reattaches one plex from the snapshot
volume, snapmyvol, to the volume, myvol:
# vxsnap -g mydg reattach snapmyvol source=myvol nmirror=1
While the reattached plexes are being resynchronized from the data in the parent
volume, they remain in the SNAPTMP state. After resynchronization is complete,
the plexes are placed in the SNAPDONE state. You can use the vxsnap snapwait
command (but not vxsnap syncwait) to wait for the resynchronization of the
reattached plexes to complete, as shown here:
# vxsnap -g mydg snapwait myvol nmirror=1
If the volume and its snapshot have both been resized (to an identical smaller or
larger size) before performing the reattachment, a fast resynchronization can
still be performed. A full resynchronization is not required. Version 20 DCO
volumes are resized proportionately when the associated data volume is resized.
For version 0 DCO volumes, the FastResync maps stay the same size, but the
region size is recalculated, and the locations of the dirty bits in the existing maps
are adjusted. In both cases, new regions are marked as dirty in the maps.
Reattaching a linked break-off snapshot volume
Unlike other types of snapshot, the reattachment operation for linked break-off
snapshot volumes does not return the plexes of the snapshot volume to the parent
volume. The link relationship is re-established that makes the snapshot volume
a mirror of the parent volume, and this allows the snapshot data to be
resynchronized. However, the snapshot volume is only readopted by its parent
volume if they are both in the same disk group.
To reattach a linked break-off snapshot volume, use the following form of the
vxsnap reattach command:
Administering volume snapshots
Creating instant snapshots
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