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Date: Fri, 6 Sep 2002 10:22:43 -0300 (BRT)
From: Rik van Riel <riel@conectiva.com.br>
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To: "Peter T. Breuer" <ptb@it.uc3m.es>
cc: Anton Altaparmakov <aia21@cantab.net>, Daniel Phillips <phillips@arcor.de>,
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       Xavier Bestel <xavier.bestel@free.fr>, <david.lang@digitalinsight.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: (fwd) Re: [RFC] mount flag "direct"
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On Fri, 6 Sep 2002, Peter T. Breuer wrote:

>    suppose that I make the FS twice as slow as before by meddling with
>    it to make it sharable
>
>    then I simply share it among 4 nodes to get a two times _speed up_
>    overall.
>
> That's the basic idea. Details left to reader.

The "detail" is lock contention. If you lock the filesystem
and invalidate the caches you'll be able to do one operation
every disk seek, across all nodes.

Chances are your 4-node system would have lower aggregate
throughput than a single node system.

Rik
-- 
Bravely reimplemented by the knights who say "NIH".

http://www.surriel.com/		http://distro.conectiva.com/

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