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Hi.

Has anyone seen any published figures for the PCI-X SCSI Raid controller
card (Feature code 5703) on a pSeries around?

I've got a 5703 with 6x 146GB disks (FC 3275). Everything is configured
for 320MB/sec busses, and the disks are split 3 & 3 on separate busses
in a RIO. The RIO is connected to a pSeries 520 server with 10GB memory
and 2x 1.5GHz Power5 processors.

The test is to configure up a reasonably large (100GB) filesystem and
use Bonnie++ to test the sequential block IO performance. I'm using JFS2
without any options, and an inline JFSLog of 64MB.

The most balanced speed I've managed to get out of the system using
hardware RAID is RAID10 (6 disks) which gives me just under 80MB/sec
read & the same for write.

Other formats don't fare as well. RAID-5 (6 disks) write drops to only
~30MB/sec, but read climbs to ~ 110MB/sec.

Raid-0 (3 disks) is a little faster than 10 at 94 write & 77 read, while
chaning the hardware stripe size from 64kB to 256kB raises the write to
115MB/sec but drops the reasd to around 55MB/sec.

That RAID-0 reading is particularly disappointing... The drives
themselves are rated at a sustained speed of 47-89MB/sec. I'd expect
when striping them across 3x spindles to at least give me some
improvement, but nothing doing...

Dropping hardware RAID completely gives me slightly better results using
AIX LVM striping. Across 3 disks with a 128kB stripe I can get 150MB/sec
write, and 77MB/sec read. Using mirroring (With MWC) pretty much kills
it (18MBsec write & 77MBsec read)... MEanwhile mirrored READING is
slower with a 64kB stripe...

It all looks like I've got or done something wrong... But I have no
published figures on the 5703 to compare it with, other than the
marketing 320MB/sec which is the bus speed & nothing else.

Are these figures in the expected ballpark?

Oh... Can you add a second PCI-X SCSI RAID 5703 to a 520's RIO & put one
of the SCSI banks on one card & one on another? If the bottleneck is the
RAID controller itself, at least then I could stripe across controllers
& get better results...

TIA

Hamish.