The most important consideration when it comes to throughput is file size.
 Lots of large files, great network transfer rates, lots of small files,
not so great network transfer rate.

We recently ran some tests on an AIX ADSM server with Magstar MP drives and
robot, 100 Mbit pipe betwixt the client and the server.  Client was a
little Netfinity, single processor, 128 MB.  I would say average file size
was on the high side of normal.  That is quite a few large files ~30-50 MB
and lots of little ones.  Single stream backup and restore of the disk
containing these files we were able to get ~6GB/hour.  With three streams
(one per disk for both backup and restore), it scaled perfectly to
~18GB/hour.  Interesting thing was direct to tape was actually a little
faster than to disk.  I was surprised about this until we discovered a
reduced raid set in our storage pool.  CPU utilization on the client
averaged high 70%.  CPU utilization on the server was equally high.

I think these numbers are high, but we were real pleased with them.

Kelly Lipp
Storage Solutions Specialists, Inc.
lipp AT storsol DOT com
www.storsol.com
(719) 531-5926