MSA500 G2 performance issues

[Andrey Vakhtitov]

Hello all. Need your help.
I have Proliant DL380 G5, SA642 and MSA500 G2 with two controllers and 4-port i/o module.
MSA500 contains 14 (HP 72GB U320 15K Universal HDD), which are organized in Raid-6 array(12 hdds) and two hot spares. (paranoic?) :)
Average read speed from array ~ 50MB/sec.
IOPS from IOMETER(4kb, 75%read, 0%random) ~ 900.

HP documentation (http://h18000.www1.hp.com/products/quickspecs/11956_div/11956_div.html) describe another IOPS for MSA - 14000 for 2-hosts and 14-hdds.

SA642 firmware - 2.84, MSA - 1.56.

Help me for speeding MSA :)

[TTr]

With the 642, you are only utilizing the external scsi i/o channel to connect to the MSA500. So there is a performance limitation there. You should first consider replacing the 642 with a 6402 and spread out the disks to two channels. Without replacing the 642, the only thing you can do is try different RAID options with fewer disks in the RAID groups and maybe use raid5.

The published IOPS from HP are the absolute maximum the MSA500 HW can do and it was achieved with special setup, 2 servers, with 2 scsi interfaces each to the MSAS500 doing concurrent i/o from all 4 SCSI channels. In real life don't expect to get anywhere near the published performance scores.

[Andrey Vakhtitov]

OK, I have a 1 SCSI port. I expect that happens to squeeze 14000/4 = 3500 IOPS. Bandwidth of PCI-X - 1066MB/s, SCSI320 - 320MB/s. If I do not think, low - 320 MB per second.
(1) How performance below this figure six times?
(2) On each MSA500 G2 controller installed 512 MB cache. How can I check speed of system cache?