From: Al Boldi <a1426z@gawab.com>
To: Ralf Gross <Ralf-Lists@ralfgross.de>
Cc: linux-kernel@vger.kernel.org, fengguang.wu@intel.com
Subject: Re: io-scheduler tuning for better read/write ratio
Date: Thu, 25 Jun 2009 16:45:40 +0300 [thread overview]
Message-ID: <200906251645.40705.a1426z@gawab.com> (raw)
In-Reply-To: <20090625072641.GB16642@p15145560.pureserver.info>
Ralf Gross wrote:
> Al Boldi schrieb:
> > Try changing /proc/sys/vm/dirty_ratio = 1
>
> $cat /proc/sys/vm/dirty_ratio
> 1
>
>
> $dstat -D md1 -d 5
> --dsk/md1--
> _read _writ
> 18M 18M
> 0 0
> 820k 101M
> 18M 113M
> 26M 73M
> 26M 110M
> 32M 100M
> 19M 111M
> 13M 117M
> 13M 142M
> 32M 88M
> 26M 99M
> 38M 58M
>
> No change. Even setting dirty_ratio to 100 didn't show any difference.
What's your readahead? Do a blockdev --getra /dev/sdX and /dev/mdX.
Try increasing it, while keeping dirty_ratio low.
Thanks!
--
Al
next prev parent reply other threads:[~2009-06-25 13:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-16 15:43 io-scheduler tuning for better read/write ratio Ralf Gross
2009-06-16 16:41 ` David Newall
2009-06-16 18:40 ` Ralf Gross
2009-06-16 18:43 ` Casey Dahlin
2009-06-16 18:56 ` Ralf Gross
2009-06-16 20:16 ` Jeff Moyer
2009-06-22 14:43 ` Jeff Moyer
2009-06-22 16:31 ` Ralf Gross
2009-06-22 19:42 ` Jeff Moyer
2009-06-23 7:24 ` Ralf Gross
2009-06-23 13:53 ` Jeff Moyer
2009-06-24 7:25 ` Ralf Gross
2009-06-24 7:57 ` Al Boldi
2009-06-25 7:26 ` Ralf Gross
2009-06-25 13:45 ` Al Boldi [this message]
2009-06-25 7:27 ` Ralf Gross
2009-06-26 2:19 ` Wu Fengguang
2009-06-26 10:44 ` Jens Axboe
2009-06-27 3:46 ` Wu Fengguang
2009-06-29 9:47 ` Ralf Gross
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