Veritas Volume Manager 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Chapter 9, Administering Volume Snapshots
Creating Instant Snapshots
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The first form of the command specifies an existing volume, snapvol, that is to be used
as the snapshot volume. See “Creating a Volume for Use as a Full-Sized Instant
Snapshot” on page 293 for details.
For example, to use the prepared volume, snap1myvol, as the snapshot for the
volume, myvol, in the disk group, mydg, use the following command:
# vxsnap -g mydg make source=myvol/snapvol=snap1myvol
For full-size instant snapshots that are created from an empty volume, background
synchronization is enabled by default (equivalent to specifying the syncing=on
attribute). If you want to move a snapshot into a separate disk group, or to turn it into
an independent volume, you must wait for its contents to be synchronized with those
of its parent volume.
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
For example, you would use the following command to wait for synchronization to
finish on the snapshot volume, snap2myvol:
# vxsnap -g mydg syncwait snap2myvol
This command exits (with a return code of zero) when synchronization of the
snapshot volume is complete. The snapshot volume may then be moved to another
disk group or turned into an independent volume.
If required, you can use the following command to verify whether the
V_PFLAG_INCOMPLETE flag is set on a volume:
# vxprint [-g diskgroup] -F%incomplete snapvol
This command returns the value off if synchronization of the volume, snapvol, is
complete; otherwise, it returns the value on.
You can also use the vxsnap print command to check on the progress of
synchronization as described in “Displaying Instant Snapshot Information (vxsnap
print)” on page 291.
See “Controlling Instant Snapshot Synchronization” on page 292 for more
information.
If you do not want to move the snapshot into a separate disk group, or to turn it into
an independent volume, specify the syncing=off attribute. This avoids creating
unnecessary system overhead. For example, to turn off synchronization when
creating the snapshot of the volume, myvol, you would use the following form of the
vxsnap make command:
# vxsnap -g mydg make source=myvol/snapvol=snap1myvol/syncing=off