On Thu, 8 Dec 1994 11:50:19 CST Keith A. Crabb said:
>I have Memorex equivalents of 3490E tape drives and am using the 3490
>extended length cartridges with data compression on the clients and am
>seeing about 800M per cartridge.  So I'd say 400M is about what you would
>expect from standard length cartridges.  You can store more on the tapes
>without data compression on the clients if you're willing to pay the
>network bandwith though.  In tests I got about 1200-1400M on a 3490
>extended cartridge but, we decided to just buy more tapes rather than
>pay the extra 30-50% of network traffic during a backup/restore.

It's true that if you turn off data compression on the clients, the ADSM
server will report that it is putting more data on each cartridge, but
that is because the server would be writing uncompressed data instead of
compressed data.  Regardless of whether data compression is being done
on the client or by IDRC, it is still the same amount of data, and should
require about the same number of cartridges.

Larry Sanders
University Computing Services
University of Missouri - Columbia