At  2:30 PM 1/11/95 -0500, Danczak, Mark wrote:
>     We are a potential ADSM user.  We are considering running ADSM under
>     AIX and utilizing 8mm tape technology.  I was wondering if anyone had
>     any recommendations or suggestions concerning the Exabyte EXB-120, the
>     Lago Datawheel, or any other ADSM tape issues.
>
>     Thanks, Mark Danczak
>             Sherwin-Williams
>             medanczak AT sherwin DOT com

Wouldn't consider buying into the old line of exabyte drives or robots at
this point. The new exabyte drives (8505XL's) have higher transfer rates, 4
times the mean time between failure ratings, are half height and front
loading. The newer robots (the 210 - 2 drives, 10 tapes; the 440 - 4
drives, 40 tapes; the 480 - 4 drives 80 tapes) use these drives. Since the
newer drives are front loading the robotic mechanism is also simpler - so
suspect this generation of robots will be far more reliable.

We are currently running a pilot project using ADSM with an RS6000 server
and the exabyte 210 robotic library (already supported by ADSM) - so far
they are performing well. I suspect ADSM support for the 440 and 480 will
follow very shortly. If all goes well and we launch a formal service we'll
likely go with a 440 with 4 drives and use the 210 for cutting offsite
copies of data.

Seems to me you need a robot with 4 drives in order for any reasonable size
service to perform well. Would recommend maintaining a large enough disk
storage pool to handle at least amount of data transferred nightly. We kick
off migrations to the tape library by lowering migration thresholds every
morning.

8 mm technology does not handle nearly as many read/write passes as other
technologies, so you have to plan on more frequent media replacement. We
haven't decided yet what that frequency will be for our server.


Cheers

Chris Krusch                             Email: krusch AT ucs.ubc DOT ca
University Computing Services            Phone: (604)822-4215