From: Hannes Dorbath <light@theendofthetunnel.de>
To: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: linux-ide-arrays@lists.math.uh.edu, xfs@oss.sgi.com,
linux-raid@vger.kernel.org, linux@vger.kernel.org
Subject: Re: Software RAID5 Horrible Write Speed On 3ware Controller!!
Date: Wed, 18 Jul 2007 12:49:29 +0200 [thread overview]
Message-ID: <469DF039.4040906@theendofthetunnel.de> (raw)
In-Reply-To: <Pine.LNX.4.64.0707180614480.7659@p34.internal.lan>
On 18.07.2007 12:23, Justin Piszcz wrote:
> I am sure one of your questions is, well, why use SW RAID5 on the
> controller? Because SW RAID5 is usually much faster than HW RAID5, at
> least in my tests:
Though that's no answer to your question, I really can't confirm that.
I'm running a 3Ware 9650 with 8x 7200 SATAs in HW RAID 6. Writes are
between 340-360MB/sec and reads peak at 430-450MB/sec. That seems to be
the absolute possible maximum those drives can deliver. The card even
seems to do some really smart stuff, as the read speed is in excess of
the physical raw speed of 6 drives.
You have done the usual settings, 3Ware recommends?
echo 64 > /sys/block/sda/queue/max_sectors_kb
echo 512 > /sys/block/sda/queue/nr_requests
echo "deadline" > /sys/block/sda/queue/scheduler
blockdev --setra 16384 /dev/sdX
Have you set the correct su,sw options for XFS?
--
Regards,
Hannes Dorbath
next prev parent reply other threads:[~2007-07-18 10:49 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-18 10:23 Software RAID5 Horrible Write Speed On 3ware Controller!! Justin Piszcz
2007-07-18 10:49 ` Hannes Dorbath [this message]
2007-07-18 16:26 ` Justin Piszcz
2007-07-18 17:18 ` Bryan J. Smith
2007-07-18 10:59 ` Al Boldi
2007-07-18 12:01 ` Justin Piszcz
2007-07-18 11:05 ` Gabor Gombas
2007-07-18 11:19 ` Justin Piszcz
2007-07-18 11:26 ` Hannes Dorbath
2007-07-18 11:32 ` Justin Piszcz
2007-07-18 11:37 ` Hannes Dorbath
2007-07-18 11:38 ` Justin Piszcz
2007-07-18 12:51 ` Robin Hill
2007-07-18 14:26 ` Gabor Gombas
2007-07-18 11:17 ` Giuseppe Ghibò
2007-07-18 11:20 ` Justin Piszcz
2007-07-18 17:57 ` Bryan J. Smith
2007-07-18 11:26 ` Sander
2007-07-18 11:35 ` Justin Piszcz
2007-07-18 12:09 ` Sander
2007-07-18 12:19 ` Justin Piszcz
2007-07-18 13:32 ` Sander
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