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From: Wolfgang Denk <wd@denx.de>
To: stefan.huebner@stud.tu-ilmenau.de
Cc: linux-raid@vger.kernel.org
Subject: Re: Optimize RAID0 for max IOPS?
Date: Wed, 19 Jan 2011 20:21:04 +0100	[thread overview]
Message-ID: <20110119192104.1FA92D30267@gemini.denx.de> (raw)
In-Reply-To: <4D361F26.3060507@stud.tu-ilmenau.de>

Dear =?ISO-8859-15?Q?Stefan_/*St0fF*/_H=FCbner?=,

In message <4D361F26.3060507@stud.tu-ilmenau.de> you wrote:
> 
> [in German:] Schätzelein, Dein Problem sind die Platten, nicht der
> Controller.
> 
> [in English:] Dude, the disks are your bottleneck.
...

Maybe we can stop speculations about what might be the cause of the
problems in some setup I do NOT intend to use, and rather discuss the
questions I asked.

> > I will have 4 x 1 TB disks for this setup.
> > 
> > The plan is to build a RAID0 from the 4 devices, create a physical
> > volume and a volume group on the resulting /dev/md?, then create 2 or
> > 3 logical volumes that will be used as XFS file systems.

Clarrification: I'll run /dev/md* on the raw disks, without any
partitions on them.

> > My goal is to optimize for maximum number of I/O operations per
> > second. ...
> > 
> > Is this a reasonable approach for such a task?
> > 
> > Should I do anything different to acchive maximum performance?
> > 
> > What are the tunables in this setup?  [It seems the usual recipies are
> > more oriented in maximizing the data troughput for large, mostly
> > sequential accesses - I figure that things like increasing read-ahead
> > etc. will not help me much here?]

So can anybody help answering these questions:

- are there any special options when creating the RAID0 to make it
  perform faster for such a use case?
- are there other tunables, any special MD / LVM / file system /
  read ahead / buffer cache / ... parameters to look for?

Thanks.

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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  parent reply	other threads:[~2011-01-19 19:21 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-18 21:01 Optimize RAID0 for max IOPS? Wolfgang Denk
2011-01-18 22:18 ` Roberto Spadim
2011-01-19  7:04   ` Wolfgang Denk
2011-01-18 23:15 ` Stefan /*St0fF*/ Hübner
2011-01-19  0:05   ` Roberto Spadim
2011-01-19  7:11     ` Wolfgang Denk
2011-01-19  8:18       ` Stefan /*St0fF*/ Hübner
2011-01-19  8:29         ` Jaap Crezee
2011-01-19  9:32           ` Jan Kasprzak
2011-01-19  7:10   ` Wolfgang Denk
2011-01-19 19:21   ` Wolfgang Denk [this message]
2011-01-19 19:50     ` Roberto Spadim
2011-01-19 22:36       ` Stefan /*St0fF*/ Hübner
2011-01-19 23:09         ` Roberto Spadim
2011-01-19 23:18           ` Roberto Spadim
2011-01-20  2:48             ` Keld Jørn Simonsen
2011-01-20  3:53               ` Roberto Spadim
2011-01-21 19:34             ` Wolfgang Denk
2011-01-21 20:03               ` Roberto Spadim
2011-01-21 20:04                 ` Roberto Spadim
2011-01-24 14:40     ` CoolCold
2011-01-24 15:25       ` Justin Piszcz
2011-01-24 20:48         ` Wolfgang Denk
2011-01-24 21:57         ` Wolfgang Denk
2011-01-24 23:03           ` Dave Chinner
2011-01-25  7:39             ` Emmanuel Florac
2011-01-25  8:36               ` Dave Chinner
2011-01-25 12:45                 ` Wolfgang Denk
2011-01-25 12:51                   ` Emmanuel Florac
2011-01-24 20:43       ` Wolfgang Denk
2011-01-25 17:10 ` Christoph Hellwig
2011-01-25 18:41   ` Wolfgang Denk
2011-01-25 21:35     ` Christoph Hellwig
2011-01-26  7:16       ` Wolfgang Denk
2011-01-26  8:32         ` Stan Hoeppner
2011-01-26  8:42           ` Wolfgang Denk
2011-01-26  9:38         ` Christoph Hellwig
2011-01-26  9:41           ` CoolCold

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