>A client has asked if data on a disk storage pool is actually erased from
>a storage pool when expiration occurs.  My intuition is that the space the
>file occupies is only marked as available for writing, but I would like to
>provide the client a more certain answer.  Does anybody  have a more
>definitive answer?

Only highly specialized software in highly secure areas would do such a thing,
if at all.  If nothing else, it would be very expensive in terms of performance,
if at all possible.  It is more than infeasible for a product to attempt to
erase the parts of a tape whose data had expired.  And, such immediate erasure
would invalidate database & storage pool recovery, which depends upon storage
pool data remaining intact over a reusedelay.  So TSM would not have any reason
to do this on a disk any more than on a tape.

You should inquire of your client why they believe any system should do such a
thing.  Reuse of space inherently "erases" old data.  Standard practices call
for obliteration or physical destruction of media leaving the physical security
of a computer site.  There's no real point in erasing unused areas of media
while the media remains in situ.

  Richard Sims, BU