Veritas Storage Foundation Intelligent Storage Provisioning 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

111Administering instant snapshots
Creating instant snapshots
Adding a snapshot to a cascaded snapshot hierarchy
To create a snapshot and push it onto a snapshot hierarchy between the original
volume and an existing snapshot volume, specify the name of the existing
snapshot volume as the value of the infrontof attribute to the
vxsnap make
command. The following example shows how to place the space-optimized
snapshot, thurs_bu, of the volume, dbvol, in front of the earlier snapshot,
wed_bu:
# vxsnap -g dbdg make source=dbvol/snapvol=thurs_bu/\
infrontof=wed_bu/cache=dbdgcache
Similarly, the next snapshot that is taken, fri_bu, is placed in front of
thurs_bu:
# vxsnap -g dbdg make source=dbvol/snapvol=fri_bu/\
infrontof=thurs_bu/cache=dbdgcache
For more information on the application of cascaded snapshots, see the Veritas
Volume Manager Administrator’s Guide.
Refreshing an instant snapshot
Refreshing an instant snapshot replaces it with another point-in-time copy of a
parent volume. To refresh one or more snapshots and make them immediately
available for use, use the following command:
# vxsnap [-g diskgroup ] refresh snapvol [source= vol ] \
[[
snapvol2 source= vol2 ]...] [sync=yes|no]
If the source volume is not specified, the immediate parent of the snapshot is
used. For full-sized instant snapshots, resynchronization is started by default.
To disable resynchronization, specify the
syncing=no attribute. This attribute is
not supported for space-optimized snapshots.
Note: The snapshot being refreshed must not be open to any application. For
example, any file system configured on the volume must first be unmounted.
It is possible to refresh a volume from an unrelated volume provided that their
sizes are compatible.
You can use the
vxsnap syncwait command to wait for the synchronization of
the snapshot volume to be completed, as shown here:
# vxsnap [-g diskgroup ] syncwait snapvol
See “Controlling instant snapshot synchronization” on page 118.