VERITAS Storage Foundation 4.1 Intelligent Storage Provisioning Administrator's Guide

Chapter 5, Administering Instant Snapshots

Creating Instant Snapshots

The %DIRTY value for snapvol1 shows that its contents have changed by 1.30% when

compared with the contents of vol1. As snapvol1 has not been synchronized with vol1, the

%VALID value is the same as the %DIRTY value. If the snapshot were partly synchronized, the

%VALID value would lie between the %DIRTY value and 100%. If the snapshot were fully

synchronized, the %VALID value would be 100%. The snapshot could then be made independent or

moved into another disk group.

Controlling Instant Snapshot Synchronization

Note Synchronization of the contents of a snapshot with its original volume is not possible for

space-optimized instant snapshots.

By default, synchronization is enabled for the vxsnap refresh and restore operation on

instant snapshots. Otherwise, synchronization is disabled unless you specify the sync=yes

attribute to the vxsnap command.

The following table shows the commands that are provided for controlling the synchronization

manually.

Command Description

vxsnap [-g diskgroup] syncpause vol Pause synchronization of a volume.

vxsnap [-g diskgroup] syncresume vol Resume synchronization of a volume.

vxsnap [-b] [-g diskgroup] syncstart vol Start synchronization of a volume. The -b

option puts the operation in the background.

vxsnap [-g diskgroup] syncstop vol Stop synchronization of a volume.

vxsnap [-g diskgroup] syncwait vol Exit when synchronization of a volume is

complete. An error is returned if vol is

invalid (for example, it is a space-optimized

snapshot), or if vol is not being

synchronized.