Veritas Volume Manager 5.0 Administrator's Guide (September 2006)
322 Administering volume snapshots
Creating instant snapshots
# vxsnap -g mydg -b addmir vol1 mirvol=prepsnap \
mirdg=mysnapdg
If the -b option is specified, you can use the vxsnap snapwait command to wait for
the synchronization of the linked snapshot volume to complete, as shown in this
example:
# vxsnap -g mydg snapwait vol1 mirvol=prepsnap \
mirdg=mysnapvoldg
2 To create a linked break-off snapshot, use the following form of the vxsnap make
command.
# vxsnap [-g diskgroup] make source=volume/snapvol=snapvol\
[/snapdg=snapdiskgroup]
The snapdg attribute must be used to specify the snapshot volume’s disk group if
this is different from that of the data volume.
For example, to use the prepared volume, prepsnap, as the snapshot for the
volume, vol1, in the disk group, mydg, use the following command:
# vxsnap -g mydg make \
source=vol1/snapvol=prepsnap/snapdg=mysnapdg
3Use fsck (or some utility appropriate for the application running on the volume) to
clean the temporary volume’s contents. For example, you can use this command with
a VxFS file system:
# fsck -F vxfs /dev/vx/rdsk/diskgroup/snapshot
4 If you require a backup of the data in the snapshot, use an appropriate utility or
operating system command to copy the contents of the snapshot to tape, or to some
other backup medium.
5 You now have the following choices of what to do with a linked break-off snapshot:
■ Refresh the contents of the snapshot. This creates a new point-in-time image of
the original volume ready for another backup. If synchronization was already in
progress on the snapshot, this operation may result in large portions of the
snapshot having to be resynchronized. See “Refreshing an instant snapshot” on
page 327 for details.
Note: This operation is not possible if the linked volume and snapshot are in
different disk groups.
■ Reattach the snapshot volume with the original volume. See “Reattaching a
linked break-off snapshot volume” on page 328 for details.
■ Dissociate the snapshot volume entirely from the original volume. This may be
useful if you want to use the copy for other purposes such as testing or report
generation. If desired, you can delete the dissociated volume. See “Dissociating
an instant snapshot” on page 330 for details.