Jim,

We see the same phenomenon with Oracle table files.  We backup those files
to "7 GB" Magstar XL tapes, but the tape drive compresses the files to fit
as much as 24 GB on one tape.  It actually put 32 GB once!

By contrast, the same drives compress our Domino data to fit 8.5 GB on a 7
GB tape.

The difference is that the Oracle files are largely empty space so they
compress down to almost nothing.  You'll see it reflected when you do
reclamation.  We reclaim two tapes containing 20+ GB of mostly Oracle data
and the "good" data fills two tapes which report "full" at about 10 GB.

Until I understood what was happening I though *SM was trying to corner the
market in "fuzzy logic".

Tab Trepagnier
TSM Administrator
Laitram Corporation