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Date: Sun, 12 Sep 2010 08:06:50 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH 1/3] block: allow migration to work with
	image	files
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To: Avi Kivity <avi@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, Juan Quintela <quintela@redhat.com>

On 09/12/2010 05:37 AM, Avi Kivity wrote:
>  On 09/11/2010 05:04 PM, Anthony Liguori wrote:
>> Image files have two types of data: immutable data that describes 
>> things like
>> image size, backing files, etc. and mutable data that includes offset 
>> and
>> reference count tables.
>>
>
> Note: even the logical size is, in principle, mutable.  If we 
> introduce external snapshots, then so are backing files?

Maybe it should be, "data the can be changed during a live migration".

Backing files and logical size shouldn't change during live migration.

But even so, I think the interface make sense.  It's basically, drop 
anything you have cached that may change during migration.  What needs 
to be read is dependent on features/format.

Regards,

Anthony Liguori