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From: David Chinner <dgc@sgi.com>
To: salmr0@bp.com
Cc: nscott@aconex.com, "Salmon, Rene" <Rene.Salmon@bp.com>, xfs@oss.sgi.com
Subject: Re: sunit not working
Date: Wed, 13 Jun 2007 09:28:17 +1000	[thread overview]
Message-ID: <20070612232817.GZ86004887@sgi.com> (raw)
In-Reply-To: <902286657-1181653953-cardhu_decombobulator_blackberry.rim.net-1527539029-@bxe120.bisx.prod.on.blackberry>

On Tue, Jun 12, 2007 at 01:12:15PM +0000, salmr0@bp.com wrote:
> 
> Thanks that helps.  Now that I know I have the right sunit and swidth I have
> a performace related question.
> 
> If I do a dd on the raw device or to the lun directy I get speeds of around
> 190-200 MBytes/sec.
> 
> As soon as I add xfs on top of the lun my speeds go to around 150
> MBytes/sec. This is for a single stream write using various block sizes on a
> 2 Gbit/sec fiber channel card.

That's for buffered I/O, right? That sounds about right - if you do two
writes, it should increase a little further. Also, direct I/O should be able
to get you to >90% of the raw device capability....

Cheers,

Dave.
-- 
Dave Chinner
Principal Engineer
SGI Australian Software Group

      parent reply	other threads:[~2007-06-12 23:28 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-11 23:55 sunit not working Salmon, Rene
2007-06-12  0:34 ` Nathan Scott
2007-06-12 13:12   ` salmr0
2007-06-12 23:21     ` Nathan Scott
2007-06-13 18:46       ` Salmon, Rene
2007-06-13 19:03         ` Sebastian Brings
2007-06-13 22:31         ` David Chinner
2007-06-12 23:28     ` David Chinner [this message]

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