HP Veritas Volume Manager 5.0 -UX 11i v3 manual Reattaching a linked break-off snapshot volume

Administering volume snapshots

Creating instant snapshots

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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

Note: 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:

#vxsnap [-gsnapdiskgroup] reattach snapvolumesnapvolume_set \ source=volumevolume_set [sourcedg=diskgroup]

The sourcedg attribute must be used to specify the data volume’s disk group if this is different from the snapshot volume’s disk group, snapdiskgroup.

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.

It is possible to reattach a volume to an unrelated volume provided that their sizes and region sizes are compatible.

For example the following command reattaches the snapshot volume, prepsnap, in the disk group, snapdg, to the volume, myvol, in the disk group,

mydg:

#vxsnap -g snapdg reattach prepsnap source=myvol sourcedg=mydg

After resynchronization of the snapshot volume is complete, the link is placed in the ACTIVE state. You can use the vxsnap snapwait command (but not vxsnap