Well, it seems I was right in regards to CPQACPI vs CPQMPK. I rebooted one of the STUSRV machines after changing it to use CPQMPK and whamo! Zippy. The TSA600 backup the previously ran at the sort of zippy 250 megs/minute ran at a much nicer 840 megs/minute, coming just shy of the old TSAFS number. The TSAFS number after switching over is 2553 megs/minute for the same STU1: data I ran with in the first tests.

And when I run three (three!) TSATESTs at the same time I get an aggregate backup speed of arounf 4800 megs/minute out of the same disk-pack. I start a fourth stream and my aggregate swells to 5800 megs/minute. All the data being played with here resides in the same disk-group on the EVA, so we're getting a good stressing of the performance of the disks themselves. I think we can squeeze even more out, since as I look at the drives on the EVA with all four streams running and they aren't completely pegged yet.

We have plenty of throughput to play with.