From: Neil Brown <neilb@cse.unsw.edu.au>
To: Phy Prabab <phyprabab@yahoo.com>
Date: Tue, 11 Jan 2005 20:54:20 +1100
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Message-ID: <16867.41549.618.539945@cse.unsw.edu.au>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Linux NFS vs NetApp
In-Reply-To: message from Phy Prabab on Monday January 10
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On Monday January 10, phyprabab@yahoo.com wrote:
> Hello!
> 
> I am trying to understand how NetApp can be so much
> better at NFS servicing than my quad Opteron 250 SAN
> attached machine.  So I need some help and some
> pointers to understand how I can make my opteron
> machine come on par (or within 70% NFS performance
> range) as that of my NetApp R200.  I have run through
> the NFS-how-to's and have heard "that is why they cost
> so much more", but I really have to consider that
> probably most of the ideas that are in the NetApp are
> common knowldge (just not in my head).
> 
> Can anyone shed some light on this?

If you want to come anything close to comparable with a Netapp, get a
few hundred Megabytes of NVRAM (e.g. www.umem.com), and configure it
as an external journal for your filesystem (I know this can be done
for ext3, I don't know about other filesystems).  Then make sure your
filesystem journals all data, not just metadata (data=journal option
to ext3).

If you use a dedicated drive (or mirrored pair) in place of the NVRAM,
you will come reasonably close.

NeilBrown
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