Steve Wolfe wrote:

The numbers that you posted from Bonnie++ , if I followed them correctly,
showed max throughputs in the 20 MB/second range. That seems awfully slow
for this sort of setup.

I noticed that, too, but then noticed that the OP seemed to be running
three copies of Bonnie++ in parallel. His command line was:

'bonnie++ -s 4G -m 3ware-swraid5-type -p 3 ; \
bonnie++ -s 4G -m 3ware-swraid5-type-c1 -y & \
bonnie++ -s 4G -m 3ware-swraid5-type-c2 -y & \
bonnie++ -s 4G -m 3ware-swraid5-type-c3 -y &'

I'm no expert, but if he's running three in parallel on the same
software RAID, I'd suspect that the total performance should be taken as
the *sum* of those three---or over 60 MB/sec.

As a comparison, I have two machines with software RAID 5 arrays, one a
2x866 P3 system with 5x120-gig drives, the other an A64 system with 8x300
gig drives, and both of them can read and write to/from their RAID 5 array
at 45+ MB/s, even with the controller cards plugged into a single 32/33 PCI
bus.

As another point of comparison: 5x73GB SCSI drives, software RAID-5,
one U160 SCSI channel, 32-bit/33-MHz bus, dual 1GHz P-III: writes at 36
MB/sec and read reads at 74 MB/sec.