Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

297Administering volume snapshots
Traditional third-mirror break-off snapshots
Traditional third-mirror break-off snapshots
The traditional third-mirror break-off volume snapshot model that is supported by the
vxassist command is shown in Figure 9-1. This also shows the transitions that are
supported by the
snapback and snapclear commands to vxassist.
Figure 9-1 Third-mirror snapshot creation and usage
The
vxassist snapstart command creates a mirror to be used for the snapshot, and
attaches it to the volume as a snapshot mirror. (The
vxassist snapabort command can
be used to cancel this operation and remove the snapshot mirror.)
Note: As is usual when creating a mirror, the process of copying the volume’s contents to
the new snapshot plexes can take some time to complete. For methods of making snapshot
plexes immediately available, see “Full-sized instant snapshots” on page 299 and “Space-
optimized instant snapshots” on page 301.
When the attachment is complete, the
vxassist snapshot command is used to create a
new snapshot volume by taking one or more snapshot mirrors to use as its data plexes. The
snapshot volume contains a copy of the original volume’s data at the time that you took
Original
volume
Refresh on
snapback
vxassist snapstart
vxassist snapback
vxassist snapclear
Original
volume
Independent
volume
Back up to disk, tape
or other media, or
use to create replica
database or file
system.
Backup
Cycle
Start
vxassist snapshot
Snapshot
volume
Snapshot
mirror