Andrew Mark Raibeck (raibeck AT CONNIX DOT COM) replied:

> My own thoughts on this:  I agree that this would be a desirable
> feature.  But I don't know how other products implement it.  ADSM
> currently doesn't inspect the contents of a file.  I suppose it's
> possible that two different files could have the same name, size,
> and modification date/time.  Maybe not WINWORD.EXE, but perhaps
> something like MYDOC.TXT.  This might not be as far-fetched as it
> sounds.  I have no idea how other vendors provide a solution to
> this.

Appreciate the thoughts.  My understanding was always that files would
be checksummed to determine uniqueness since you obviously can't count
on having unique fileid - date - size characteristics.

> The other issue is that you might want to store certain clients'
> data in one storage pool, and another client's data in a different
> storage pool.  If they happen to have duplicate files, and you
> keep only one copy, then the backup can exist in only one storage
> pool.  So any implementation of this feature would have to be
> optional, perhaps at the management class level.

I guess I would envision a copy in each storage pool.  Scenario would be
something like this.  Backup client sends file to server.  Server checks
destination file pool for a identical file (same name, date, size, and
checksum).  If it already exists in the pool then the data is discarded
and the server simply remembers that this client location "owns" a copy
of the backed-up file.

> In the long run, most of your client data will wind up on tape,
> anyway, which is cheap (relatively speaking).  And as tape
> densities increase further, the number of tapes required to house
> all this data will shrink.  So except for the initial time it
> takes to get a full backup of a client, this may or may not be as
> big an inhibitor as it seems.  Just another way of looking at
> things.

Do you think I am going to have trouble with managing catalogs, and
doing routine housekeeping on the server if I have 4,000 clients that
have all backed up the entire contents of their hard drive(s)?

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Terry A. Moore             |      "I believe OS/2 is destined to be the
Sr. I/S Tech Specialist    |      most important operating system, and
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