[Gllug] Tweaking a 3Ware 9690SA system..

[Martyn Drake]

Has anybody had experience of squeezing every last drop of performance
from a 3Ware 9690SA SAS controller?  All the disks are SAS, running at
the full 3Gbps,  and the array is HP StorageWorks MSA60.  However,
after numerous tweaks to both the controller settings (at one case
disabling much of the protection systems on the 9690SA in favour of
performance I/O) and various tweaks to the 2.6 kernell:

echo "64" > /sys/block/sda/queue/max_sectors_kb
blockdev --setra 4096 /dev/sda
echo "1024" > /sys/block/sda/queue/nr_requests
echo "deadline" > /sys/block/sda/queue/scheduler
echo 20 > /proc/sys/vm/dirty_background_ratio
echo 60 > /proc/sys/vm/dirty_ratio

the best I can get from sequential block write is around 230MB/s mark,
which seems awfully low.  The RAID 5 array has been set-up with a 64K
stripe.  I'm using the latest driver directly from 3Ware.

I'll admit that this is my first time exposed to 3Ware kit, so am not
terribly familiar with it's reputation.  One thing I haven't tried as
yet is to try kernel version 2.6.23.14.  Mainly because there is a lot
of custom infiniband stuff that needs to remain in place, and secondly
I'm trying to keep to the stock RHEL kernels wherever possible.

Regards,

Martyn
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Skype  : mbdrake
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