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Date: Thu, 09 Sep 2010 18:48:17 +0200
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Subject: [Qemu-devel] Re: [RFC] qed: Add QEMU Enhanced Disk format
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To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel@nongnu.org, Avi Kivity <avi@redhat.com>, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

On 09/09/2010 02:49 PM, Anthony Liguori wrote:
> We should optimize for the future. That means a btrfs file system and/or
> enterprise storage.

So we should just implement a copy-on-read wrapper that generates a 
sparse raw image and uses FIEMAP (or whatever it is called these days) 
to test for the presence of extents.  Then you let btrfs handle 
everything else...

Paolo