On Wed, Jun 27, 2007 at 08:57:24PM +0200, Pierre-Philipp Braun wrote:
> Hi Quentin and Manuel,
> 
> Quoting Manuel Bouyer (27/06/2007 20:21),
> >>bsdp# time dd if=/dev/zero of=lala.zero count=100 bs=1024k
> >>100+0 records in
> >>100+0 records out
> >>104857600 bytes transferred in 7.251 secs (14461122 bytes/sec)
> >>        7.26 real         0.00 user         0.34 sys
> >
> >What kind of disk and array do you have ? On dell 2950 I get about 
> >70/80MB/s
> >on a raid5 array.
> 
> two SAS attached disks (no more info from home), 140GB each, as RAID-1.
> 
> >Do you have the battery backup for the cache ?
> 
> ??? I don't know

You'll have to check, and also if the controller is in write-throuh or
write-back mode.

> 
> >>bench.sh:
> >>#!/bin/sh
> >>time dd if=/dev/zero of=lala.zero count=100 bs=1024k &
> >>time dd if=/dev/zero of=lala2.zero count=100 bs=1024k
> >>rm lala.zero
> >>rm lala2.zero
> >
> >I suspect with this, you only check the memory bandwidth of the system.
> >The data may not reach the disk at all.
> 
> I remember a tar xjf pkgsrc.tar.bz2 took ages, I had to stop it.

What I meant is that this check on linux doens't mean much. As already
suggected use a real disk benchmark to know how the disk performs under
linux.

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--