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Date: Wed, 21 May 2008 22:42:35 +0200
From: Andrea Arcangeli <andrea@qumranet.com>
Subject: Re: [Qemu-devel] Re: [PATCH][v2] Align file accesses with
	cache=off (O_DIRECT)
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Laurent Vivier <Laurent.Vivier@bull.net>, Dave Hansen <haveblue@us.ibm.com>, qemu-devel@nongnu.org, Blue Swirl <blauwirbel@gmail.com>, Paul Brook <paul@codesourcery.com>

On Wed, May 21, 2008 at 03:35:33PM -0500, Anthony Liguori wrote:
> Or if multiple guests are using the same backing file (imagine each guest 
> has it's own qcow file backed to a common one).  Or if we had a more 
> advanced storage system that did something like content addressable 
> storage.

Agreed. At least the pagecache sharing among different guests, can be
achieved with ksm too though, even if they don't share any qcow.