Now that's a very good question.  During my LTO vs. SDLT performance
testing, I discovered my first bottleneck at the RAID5 array. I was
surprised by this to some extent as I didn't expect it to be so bad.  So
enter RAID for storage pools cautiously.  We are using RAID in our
configurations, but only for the OS and DB/Log volumes.  We're using JBOD
for storage pool volumes.

As for your specific questions, I don't have the answer.  Remember that TSM
is going to "stripe" data on the volumes: a client will write txngroupmax
files per volume and move to the next (typically.  This may vary a bit, but
you get the idea).  Since it is striping the data, you want to be careful
how much you stripe it underneath.  Lots of head thrashing can occur.

Kelly J. Lipp
Storage Solutions Specialists, Inc.
PO Box 51313
Colorado Springs, CO 80949
lipp AT storsol DOT com or kelly.lipp AT storserver DOT com
www.storsol.com or www.storserver.com
(719)531-5926
Fax: (240)539-7175