MSA2000 Array performance

[Mohan Wickramasinghe]

Hi
We have the following setup

Summary:
2 HP Proliant 585 G6 server with 2 HBA cards on each server

1 MSA2000sa G2 raid array with 22 SAS small form factor disk

4 mini-SAS cables

Details:

MSA2000sa G2(SKU: AJ949A),
MSA2324 controllers (SKU: AJ808A),
73GB SAS drives 15k small form factor,
Dual port HBA cards SC08Ge (SKU: 488765B21)
mini-SAS cables (SKU: 419570-B21)

Cable connection:
From 1 port in each HBA card, to 1 port on the 2 controllers on MSA box

server 1 hba card 1 -> controller A, port 1
server 1 hba card 2 -> controller B, port 1

server 2 hba card 1 -> controller A, port 2
server 2 hba card 2 -> controller B, port 2

so there are 2 hba ports (on each server) and 2 controller ports (on the 2 controllers) free

the 2 servers have linux installed and using multipath to connect to the volumes on the MSA.
currently the volumes are on vdisks which are configured as RAID 10 using six 73GB SAS drives SFF at 15k as labeled.

once the LUNs are seen in /dev/mapper/3600xxx
we formated them in ext3 and mounted.

then we ran the dd command as follows to check the speeds

for example 1 volume was 120GB and the did

dd if=/dev/zero bs=8k count=157xxxxx of=dd.file

and the resulting speed was around 140Mbps

we see a very high I/O wait and the load average goes high during normal operation

I/O wait is around 60% as seen in iostat command.

please advice.
thank you