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Date:      Sat, 19 Nov 2005 13:38:25 +0100
From:      =?ISO-8859-1?Q?Johan_Str=F6m?= <johan@stromnet.org>
To:        Pawel Jakub Dawidek <pjd@FreeBSD.org>
Cc:        freebsd-stable@freebsd.org
Subject:   Re: Page fault, GEOM problem??
Message-ID:  <A94ACBF7-19F7-4A1C-9CEF-83B0DD0CF0AC@stromnet.org>
In-Reply-To: <20051119013552.GC735@garage.freebsd.pl>
References:  <991F35AA-151B-4AEA-82BD-5F4AEDF28424@stromnet.org> <a78074950511180117r6d64db25o4ae37c0c5998e002@mail.gmail.com> <74994962-5050-47BD-897B-DE3880B9EBD5@stromnet.org> <a78074950511180943r57fd9d03r64efcc705001bc35@mail.gmail.com> <A6F22EE2-B1E6-44B5-B4C2-E77E1A24FEBB@stromnet.org> <1132353600.903.19.camel@genius1.i.cz> <BEE8C957-9DB5-4A08-AAAE-A1E524F4E092@stromnet.org> <20051119013552.GC735@garage.freebsd.pl>

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On 19 nov 2005, at 02.35, Pawel Jakub Dawidek wrote:

> On Sat, Nov 19, 2005 at 01:55:57AM +0100, Johan Str=F6m wrote:
<snip>
> +> I just noticed another thing... My disk performance... sucks! :P
> +>
> +> Some examples (from an otherwise unloaded system):
> +>
> +> root@elfi:/home/johan$ time dd if=3D/dev/zero of=3Dbigfile.zero =20
> bs=3D1024 count=3D1000000
> +> 1000000+0 records in
> +> 1000000+0 records out
> +> 1024000000 bytes transferred in 77.014797 secs (13296146 bytes/sec)
>
> You won't get more with such small block size. Try bs=3D128k.

Hi
Can't say that a bigger blocksize did much better..

root@elfi:/home/johan$ time dd if=3D/dev/zero of=3Dbigfile.zero bs=3D128k =
=20
count=3D10000
10000+0 records in
10000+0 records out
1310720000 bytes transferred in 98.519181 secs (13304211 bytes/sec)

root@elfi:/home/johan$ time dd if=3D/dev/zero of=3Dbigfile.zero bs=3D512k =
=20
count=3D10000
^C3587+0 records in
3587+0 records out
1880621056 bytes transferred in 145.049578 secs (12965367 bytes/sec)

root@elfi:/home/johan$ time dd if=3D/dev/zero of=3Dbigfile.zero bs=3D50k =
=20
count=3D10000
10000+0 records in
10000+0 records out
512000000 bytes transferred in 38.536217 secs (13286203 bytes/sec)

All this time, iostats MB/s column wouldnt go over 0.24MB/s...

Back on GENERIC:

root@elfi:/home/johan$ time dd if=3D/dev/zero of=3Dbigfile.zero bs=3D128k =
=20
count=3D10000
10000+0 records in
10000+0 records out
1310720000 bytes transferred in 99.497358 secs (13173415 bytes/sec)

root@elfi:/home/johan$ time dd if=3D/dev/zero of=3Dbigfile.zero bs=3D512k =
=20
count=3D1000
1000+0 records in
1000+0 records out
524288000 bytes transferred in 39.019239 secs (13436654 bytes/sec)

Still slow.. However, iostat goes up as high as 5.64MB/s on each disk =20=

in the mirror.



>
> --=20
> Pawel Jakub Dawidek                       http://www.wheel.pl
> pjd@FreeBSD.org                           http://www.FreeBSD.org
> FreeBSD committer                         Am I Evil? Yes, I Am!




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