On Wed, 18 Jul 2007, Gabor Gombas wrote:
On Wed, Jul 18, 2007 at 06:23:25AM -0400, Justin Piszcz wrote:
I recently got a chance to test SW RAID5 using 750GB disks (10) in a RAID5
on a 3ware card, model no: 9550SXU-12
The bottom line is the controller is doing some weird caching with writes
on SW RAID5 which makes it not worth using.
Did you use the settings documented in
http://www.3ware.com/KB/article.aspx?id=11050 ? Setting nr_requests and
the deadline scheduler doubled the seq write performance for me. Do you
have the latest firmware? Firmware updates can improve performance - at
least for RAID5/6; I somewhat doubt that they care about JBOD
performance that much...
Gabor
--
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MTA SZTAKI Computer and Automation Research Institute
Hungarian Academy of Sciences
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For the HW RAID tests (2) at the bottom of the e-mail, no, I did not set
nr_requests or use the deadline scheduler.
For the SW RAID tests, I applied similar optimizations, I am probably not
at the latest firmware. The main thing I wanted to use though was SW RAID
because the card itself offers so many ports, however, with write speed
being that slow I am not sure its a good idea.
Justin.
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