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From: Justin Piszcz <jpiszcz@lucidpixels.com>
To: Dexter Filmore <Dexter.Filmore@gmx.de>
Cc: linux-raid@vger.kernel.org
Subject: Re: below 10MB/s write on raid5
Date: Mon, 11 Jun 2007 10:07:24 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.64.0706111007010.31708@p34.internal.lan> (raw)
In-Reply-To: <200706111606.11006.Dexter.Filmore@gmx.de>



On Mon, 11 Jun 2007, Dexter Filmore wrote:

>> 10gb read test:
>>
>> dd if=/dev/md0 bs=1M count=10240 of=/dev/null
>>
>> What is the result?
>
> 71,7MB/s - but that's reading to null. *writing* real data however looks quite
> different.
>
>>
>> I've read that LVM can incur a 30-50% slowdown.
>>
> Even then the 8-10MB/s I get would be a little low.
>
>
>
> -- 
> -----BEGIN GEEK CODE BLOCK-----
> Version: 3.12
> GCS d--(+)@ s-:+ a- C++++ UL++ P+>++ L+++>++++ E-- W++ N o? K-
> w--(---) !O M+ V- PS+ PE Y++ PGP t++(---)@ 5 X+(++) R+(++) tv--(+)@
> b++(+++) DI+++ D- G++ e* h>++ r* y?
> ------END GEEK CODE BLOCK------
>
> http://www.stop1984.com
> http://www.againsttcpa.com
>

Would it be possible to trash the LVM and write directly to the MD device? 
I'd be really curious to see what it gets with XFS ontop of MD.

Justin.

  reply	other threads:[~2007-06-11 14:07 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-11 12:46 below 10MB/s write on raid5 Dexter Filmore
2007-06-11 12:47 ` Justin Piszcz
2007-06-11 13:28   ` Dexter Filmore
2007-06-11 13:29     ` Justin Piszcz
2007-06-11 13:45       ` Jon Nelson
2007-06-11 13:53         ` Justin Piszcz
2007-06-11 14:06       ` Dexter Filmore
2007-06-11 14:07         ` Justin Piszcz [this message]
2007-06-11 22:24       ` Nix
2007-06-12  2:35         ` Jon Nelson
2007-06-13 23:54           ` Nix
2007-06-14  9:15             ` Michael Tokarev
2007-06-13 23:55           ` Nix
2007-06-12 17:16 ` Bill Davidsen
2007-06-12 17:14   ` Justin Piszcz

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