Date: Wed, 12 Mar 2008 23:32:52 -0700 (PDT)
From: david@lang.hm
To: Daniel Phillips <phillips@phunq.net>
cc: David Newall <davidn@davidnewall.com>, Chris Friesen <cfriesen@nortel.com>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, linux-kernel@vger.kernel.org
Subject: Re: [ANNOUNCE] Ramback: faster than a speeding bullet
In-Reply-To: <200803122317.24849.phillips@phunq.net>
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References: <200803092346.17556.phillips@phunq.net> <200803121556.15547.phillips@phunq.net> <47D8BF76.8040105@davidnewall.com> <200803122317.24849.phillips@phunq.net>
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On Wed, 12 Mar 2008, Daniel Phillips wrote:

> On Wednesday 12 March 2008 22:45, David Newall wrote:
>
>> Your idea seems predicated on throwing large amounts of RAM at the
>> problem.  What I want to know is this: Is it really 25 times faster than
>> ext3 with an equally huge buffer cache?
>
> Yes.

this I don't understand. what makes your approach 25x faster?

looking at the comparison of a 500G filesystem with 500G of ram allocated 
for a buffer cache.

yes, initially it will be a bit slower (until the files get into the 
buffer cache), and if fsync is disabled all writes will go to the buffer 
cache (until writeout hits)

I may be able to see room for a few percent difference, but not 2x, let 
alone 25x.

David Lang
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