When to use the ComplianceClock

You use the ComplianceClock for performing various SnapLock operations.

The following table describes these operations:

Operations	Description
Checking the expiration status of a WORM file	To check whether a WORM file has expired, you compare the retention time of the file with the ComplianceClock. If the ComplianceClock is not set or is less than the retention time, the file has not expired.
Committing a file to WORM (ctime)	When you commit a file to WORM, the ComplianceClock is written to the ctime field of the file.
Destroying a SnapLock Compliance volume	To check whether a SnapLock Compliance volume can be destroyed, you compare destroyable, its destroy time (equivalent to retention time) with the ComplianceClock. If the ComplianceClock is not set or is less than the volume destroy time, the volume cannot be destroyed.
Autocommitting a file to WORM	When autocommitting a file to WORM, you compare the value (file's ctime plus autocommit period) with the ComplianceClock. The file is committed to WORM if the ComplianceClock value is less than the value. If the ComplianceClock is not set, system time is used.
Creating a SnapLock Compliance volume	The ComplianceClock must be initialized before you can create a SnapLock Compliance volume.
SnapLock for Snapshot copies	The ComplianceClock must be initialized before you can commit Snapshot copies to WORM.
Volume SnapMirror	Volume SnapMirror works at the block level. Therefore, the ComplianceClock value is automatically transferred from the volume SnapMirror source volume to the volume SnapMirror destination volume.
Volume SnapMirror to a SnapLock Compliance volume	In Data ONTAP 7.2.5, Data ONTAP 7.3.1, and later releases, the ComplianceClock must be initialized on the destination storage system before you can do a volume SnapMirror transfer that has a SnapLock Compliance volume as the destination.
Qtree SnapMirror	In Data ONTAP 7.2.5, Data ONTAP 7.3.1, and later releases, the qtree SnapMirror protocol is upgraded to transfer the ComplianceClock from the source to the destination. This adjusts the ComplianceClock of the destination storage system on qtree snapmirror break.