Last week there was a request on the list for performance figures
backing up large files to an STK9710 tape library with  DLT 7000 drives.
Here are some real-life numbers:


Our server is an RS6000 J30 running AIX 4.1.5.
Our ADSM is 2.1.5.12 with the ADSM Enhanced server add-on at PTF 12.

The client was WinNT 4.0 on a Compaq Proliant 4500R model 5/100-2,
running the adsm 32-bit client at 2.1.0.6.
The client disk files are on STK/Clarion RAID-5 disk, with some on-board
cache.

Client and server are on different 16 MB token ring segments connected
via a Centillion token-ring switch.

We backed up three 2.5 GB files (one after the other) from the NT 4.0
client direct to one DLT7000 tape in the 9710.
The files contain data that is already compressed by the creating
software.
Moving the 3 files/7.5 GB direct to tape took 2 hours.

I haven't done anything that I know of to tune anything.
Your mileage may vary.