VERITAS Volume Manager 3.5 Administrator's Guide (September 2004)

Understanding VERITAS Volume Manager
Volume Snapshots
Chapter 1 51
Volume Snapshots
The volume snapshot model is shown in Figure 1-32, “Snapshot Creation
and the Backup Cycle,” This figure also shows the transitions that are
supported by the snapback and snapclear commands to vxassist.
Figure 1-32 Snapshot Creation and the Backup Cycle
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.)
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 the snapshot. If more
than one snapshot mirror is used, the snapshot volume is itself mirrored.
Original
volume
Refresh on
snapback
snapstart
snapback
snapclear
Original
volume
Independent
volume
Back up to disk,
tape or other
medium, or use
to create replica
database or file
system.
Backup
Cycle
START
snapshot
Snapshot
volume
Snapshot
mirror