|
From: | Anthony Liguori |
Subject: | Re: [Qemu-devel] [RFC] qed: Add QEMU Enhanced Disk format |
Date: | Wed, 08 Sep 2010 11:30:10 -0500 |
User-agent: | Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.11) Gecko/20100713 Lightning/1.0b1 Thunderbird/3.0.6 |
On 09/08/2010 10:38 AM, Christoph Hellwig wrote:
On Wed, Sep 08, 2010 at 12:15:13PM +0100, Stefan Hajnoczi wrote:In-place writes overwrite old data in the image file. They do not allocate new clusters or update any metadata. This is why write performance is comparable to raw in the long run.Only if qed doesn't cause additional fragmentation. Which it currently does.
http://wiki.qemu.org/Features/QED/OnlineDefragIs 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.
Regards, Anthony Liguori
[Prev in Thread] | Current Thread | [Next in Thread] |