Message-Id: <200107162111.f6GLBPQ24732@jen.americas.sgi.com>
To: =?iso-8859-1?Q?Ragnar_Kj=F8rstad?= <xfs@ragnark.vestdata.no>
cc: Mike Gigante <mg@smack.melbourne.sgi.com>,
   Simon Matter <simon.matter@ch.sauter-bc.com>, "P.Dixon" <P.Dixon@qmw.ac.uk>,
   linux-xfs@oss.sgi.com
Subject: Re: benchmarks 
In-Reply-To: Message from =?iso-8859-1?Q?Ragnar_Kj=F8rstad?= <xfs@ragnark.vestdata.no> 
   of "Mon, 16 Jul 2001 22:41:26 +0200." <20010716224126.E14564@vestdata.no> 
Date: Mon, 16 Jul 2001 16:11:25 -0500
From: Steve Lord <lord@sgi.com>
Sender: owner-linux-xfs@oss.sgi.com
Precedence: bulk


> 
> > The mongo benchmarks use relatively small files. XFS scales very well to
> > large files/directories, but that benchmark sticks to small scale stuff.
> > It *seems* to show ReiserFS in the best possible light and the XFS results
> > don't seem to reflect anything like real world experience (except that it
> > correctly highlights the relatively slow delete performance of XFS!)
> 
> I partly disagree. mongo tests filesystem performace - benchmarks that
> test writing really big files is mostly testing your hardware. The
> filesystem still matters, but not so much as on small files. I think
> the difference between ext2/xfs/reiserfs is less than 10%. (ext3 with
> datalogging may be a different story though).
> 
> 

mongo tests how the filesystem behaves under the endcase of continuous
metadata load from an application which is doing nothing with the data
except reading it and writing it. It is a rare application which behaves
in this way, but it is a very common benchmark, the filesystem is there
to provide service to applications, not to consume all the resources
of the machine.

Note that I am not arguing for one filesystem or another, just commenting
on the nature of filesystem benchmarks, reiserfs is good for some things,
XFS is good for others.

Steve

> 
> -- 
> Ragnar Kjorstad
> Big Storage