Snapshot recovery

There are two types of possible damage to the snapshot from which Data Archive can recover:

• Snapshot times in the future. Accidentally moving the Data Archive system time into the future can cause this; at a minimum all points collected locally will be in the future. Snapshot events are replaced when a newer value is received; therefore these events remain in the snapshot until actual time catches up. Events earlier than snapshot time bypass compression. Events that bypass compression can put a large load on Data Archive.

• Damaged or corrupted snapshot file (piarcmem.dat). Corruption may be caused by disk or power failures.