Steve --

We are:

AIX 4.3.3 Server (S7A, 4 cpu, 4 GB, with two Gb ethernet and 7 100 Mb
ethernet -- most of this because it's also our SAP fallover system) with an
STK 9710 (9 Quantum DLT-7000 drives) and a Cisco 6509. We haven't done vlans
on the 6509 yet, but I have the Gb ethernet adapters in two seperate IP
networks.

AIX 4.3.3 Client (S7A, 8 cpu, 4 GB, two Gb ethernet, 5 100 Mb ethernet) with
over 600 GB disk allocated to an IBM ESS, split over 3 fiber-channel
adapters.

I use backint (now TDP for SAP/R3) and get an average of 9 MB/sec per tape
drive (maximum rated performance for the drives)-- three sessions on one Gb
ethernet, two on the other (five tape drives in use at a time).

I'm running the default network tuning for AIX 4.3.3.

Are you doing data compression on the client? If so, turn it off and let the
tape drives do the data compression. Can the EMC support sustained read
speeds of 80 GB/hour? I see steady-state reads of up to 15 MB/sec on my ESS
arrays during the backups. Can one 3590E handle 80 GB/hour sustained write
throughput (I haven't looked at the specs in quite a while)?

The Gb ethernet shouldn't be the bottleneck. I'd suspect the tape subsystem
(how many drives in use concurrently? How are they connected? How many on
each interface, and what is it rated at? I have two drives per SCSI adapter
and the adapters are rated at 20 MB/sec, so I'm limited by both the tape
drives and the adapters). The EMC 3700 should be able to keep everything
else busy without breaking into a sweat itself.

Tom Kauffman
NIBCO, Inc.