NW 6.5 SP3

I make regular snapshots of NSS Pool "DATA". The snapshot pool is "BAK".

I've had no trouble making snapshots, nor mounting them, etc.

However, twice now, without warning, all my snapshots have suddenly and
irrevocably disappeared. This has happened literally overnight, and without
any associated action on my part.

I don't find any related TID's. Has anyone experienced or heard of such a

I don't find any evidence of corruption in either the data or the snapshot

What could be causing this?