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Re: [Xen-devel] Domain save/migrate issue

To: Steven Hand <Steven.Hand@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Domain save/migrate issue
From: Daniel Veillard <veillard@xxxxxxxxxx>
Date: Tue, 14 Feb 2006 09:57:05 -0500
Cc: Noam Taich <noam.taich@xxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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On Tue, Feb 14, 2006 at 02:44:29PM +0000, Steven Hand wrote:
> > On Tue, Feb 14, 2006 at 06:08:06AM -0800, Noam Taich wrote:
> > it would not be atomic anymore). Is there any strong reason a saved domain
> > must not be left running ?
> Unless you also have some way to simulataneously snapshot the file
> system, it is not safe to allow the guest to continue and then later
> resume the checkpointed version. 

  The problem already exists if you resume twice a guest from an image.
Restraining the API doesn't fix the problem, it just limits the probability
of hitting it by mistake. I'm not sure there is any way we can garantee
100% safe operations in all case, most FSes don't have snapshotting
capabilities anyway.


Daniel Veillard      | Red Hat http://redhat.com/
veillard@xxxxxxxxxx  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
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