From: Phillip Susi <psusi@cfl.rr.com>
To: Max Waterman <davidmaxwaterman+kernel@fastmail.co.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: io performance...
Date: Wed, 18 Jan 2006 10:19:22 -0500 [thread overview]
Message-ID: <43CE5C7A.5060608@cfl.rr.com> (raw)
In-Reply-To: <43CDED23.5060701@fastmail.co.uk>
Right, the kernel does not know how many disks are in the array, so it
can't automatically increase the readahead. I'd say increasing the
readahead manually should solve your throughput issues.
Max Waterman wrote:
>
> I left the stripe size at the default, which, I believe, is 64K bytes;
> same as your fakeraid below.
>
> I did play with 'blockdev --setra' too.
>
> I noticed it was 256 with a single disk, and, with s/w raid, it
> increased by 256 for each extra disk in the array. IE for the raid 0
> array with 4 drives, it was 1024.
>
> With h/w raid, however, it did not increase when I added disks. Should I
> use 'blockdev --setra 320' (ie 64 x 5 = 320, since we're now running
> RAID5 on 5 drives)?
>
next prev parent reply other threads:[~2006-01-18 15:19 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-16 7:35 io performance Max Waterman
2006-01-16 7:32 ` Jeff V. Merkey
2006-01-17 13:57 ` Jens Axboe
2006-01-17 19:17 ` Jeff V. Merkey
2006-01-16 8:35 ` Pekka Enberg
2006-01-17 17:06 ` Phillip Susi
2006-01-18 7:24 ` Max Waterman
2006-01-18 15:19 ` Phillip Susi [this message]
2006-01-20 5:58 ` Max Waterman
2006-01-20 13:42 ` Ian Soboroff
2006-01-25 6:36 ` Max Waterman
2006-01-25 14:19 ` Ian Soboroff
2006-01-25 13:09 ` Bernd Eckenfels
2006-01-18 3:02 ` Max Waterman
2006-01-18 4:30 ` Jeff V. Merkey
2006-01-18 5:09 ` Max Waterman
2006-01-18 4:37 ` Jeff V. Merkey
2006-01-18 7:06 ` Max Waterman
2006-01-18 9:21 ` Alan Cox
2006-01-18 15:48 ` Phillip Susi
2006-01-18 16:25 ` Bartlomiej Zolnierkiewicz
2006-01-19 0:48 ` Adrian Bunk
2006-01-19 13:18 ` Max Waterman
[not found] <5vx8f-1Al-21@gated-at.bofh.it>
[not found] ` <5wbRY-3cF-3@gated-at.bofh.it>
[not found] ` <5wdKh-5wF-15@gated-at.bofh.it>
2006-01-19 1:58 ` Robert Hancock
2006-01-19 13:14 ` Max Waterman
2006-01-19 14:08 ` Alan Cox
2006-01-20 4:09 ` Max Waterman
2006-01-20 4:27 ` Alexander Samad
2006-01-20 12:52 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2006-01-19 11:39 Al Boldi
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