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Date: Wed, 08 Sep 2010 15:28:50 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [RFC] qed: Add QEMU Enhanced Disk format
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To: Christoph Hellwig <hch@lst.de>
Cc: Kevin Wolf <kwolf@redhat.com>, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel@nongnu.org, Alexander Graf <agraf@suse.de>, Avi Kivity <avi@redhat.com>

On 09/08/2010 03:23 PM, Christoph Hellwig wrote:
> On Wed, Sep 08, 2010 at 11:30:10AM -0500, Anthony Liguori wrote:
>    
>> http://wiki.qemu.org/Features/QED/OnlineDefrag
>>
>> Is a spec for a very simple approach to online defrag that I hope we can
>> implement in the near future.  I think that once we have the mechanisms
>> to freeze clusters and to swap clusters, implementing much more
>> sophisticated defragmentation algorithms will become easy.
>>      
> This image defragmentation might in fact cause even more fragmentation
> at the filesystem layer.
>    

That's a good point.  Is there a reasonable way to do this cooperatively 
with the underlying filesystem?

BTW, the same problem would occur for sparse file system images, no?

Regards,

Anthony Liguori