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From: "Arkadiusz Miśkiewicz" <arekm@maven.pl>
To: xfs@oss.sgi.com, xfs@pzystorm.de
Cc: linux-raid@vger.kernel.org, stan@hardwarefreak.com
Subject: Re: XFS blocked task in xlog_cil_force_lsn
Date: Fri, 20 Dec 2013 23:43:47 +0100	[thread overview]
Message-ID: <201312202343.47895.arekm@maven.pl> (raw)
In-Reply-To: <52B41B67.9030308@pzystorm.de>

On Friday 20 of December 2013, Kevin Richter wrote:

> >> $ cat /sys/block/md2/md/stripe_cache_size
> >> 256
> > 
> > 256 is the default and it is way too low.  This is limiting your write
> > througput.  Increase this to a minimum of 1024 which will give you a
> > 20MB stripe cache buffer.  This should become active immediately.  Add
> > it to a startup script to make it permanent.

> > $ echo 256 > /sys/block/md2/md/stripe_cache_size
> > $ time cp -a /olddisk/testfolder /6tb/foo1/
> > real    25m38.925s
> > user    0m0.595s
> > sys     1m23.182s
> > 
> > $ echo 1024 > /sys/block/md2/md/stripe_cache_size
> > $ time cp -a /olddisk/testfolder /raid/foo2/
> > real    7m32.824s
> > user    0m0.438s
> > sys     1m6.759s
> > 
> > $ echo 2048 > /sys/block/md2/md/stripe_cache_size
> > $ time cp -a /olddisk/testfolder /raid/foo3/
> > real    5m32.847s
> > user    0m0.418s
> > sys     1m5.671s
> > 
> > $ echo 4096 > /sys/block/md2/md/stripe_cache_size
> > $ time cp -a /olddisk/testfolder /raid/foo4/
> > real    5m54.554s
> > user    0m0.437s
> > sys     1m6.268s
> 
> The difference is really amazing! So 2048 seems to be the best choice.
> 60GB in 5,5minutes are 180MB/sek. That sounds a bit high, doesnt it?
> The RAID only consist of 5 SATA disks with 7200rpm.

I wonder why kernel is giving defaults that everyone repeatly recommends to 
change/increase? Has anyone tried to bugreport that for stripe_cache_size 
case?

-- 
Arkadiusz Miśkiewicz, arekm / maven.pl

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  parent reply	other threads:[~2013-12-20 22:43 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-18  2:05 XFS blocked task in xlog_cil_force_lsn Kevin Richter
2013-12-18  3:38 ` Stan Hoeppner
2013-12-18 10:27   ` Kevin Richter
2013-12-19 14:11     ` Stan Hoeppner
2013-12-20 10:26       ` Kevin Richter
2013-12-20 12:36         ` Stan Hoeppner
2013-12-21  5:30           ` Dave Chinner
2013-12-22  9:18             ` Stan Hoeppner
2013-12-22 20:14               ` Dave Chinner
2013-12-22 21:01               ` Michael L. Semon
2013-12-22  2:35           ` Kevin Richter
2013-12-22  8:12             ` Stan Hoeppner
2013-12-22 14:10               ` Kevin Richter
2013-12-22 17:29                 ` Stan Hoeppner
2013-12-20 22:43         ` Arkadiusz Miśkiewicz [this message]
2013-12-21 11:18           ` md-RAID5/6 stripe_cache_size default value vs performance vs memory footprint Stan Hoeppner
2013-12-21 11:18             ` Stan Hoeppner
2013-12-21 12:20             ` Piergiorgio Sartor
2013-12-21 12:20               ` Piergiorgio Sartor
2013-12-22  1:41             ` Stan Hoeppner
2013-12-26  8:55             ` Christoph Hellwig
2013-12-26  9:24               ` Stan Hoeppner
2013-12-26 22:14                 ` NeilBrown
2013-12-18  8:33 ` XFS blocked task in xlog_cil_force_lsn Stefan Ring
2013-12-18 22:21 ` Dave Chinner
  -- strict thread matches above, loose matches on Subject: below --
2012-04-16  6:48 Stefan Priebe - Profihost AG
2012-04-16 23:56 ` Dave Chinner
2012-04-17  8:19   ` Stefan Priebe - Profihost AG
2012-04-17  8:32     ` Dave Chinner
2012-04-17  9:19       ` Stefan Priebe - Profihost AG

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