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Date: Wed, 29 Jul 2009 21:24:00 +0200
Message-ID: <5b31733c0907291224h340921f0j72195618b0b6cd2a@mail.gmail.com>
Subject: Re: [Qemu-devel] [PATCH v2] make windows notice media change
From: Filip Navara <filip.navara@gmail.com>
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To: Paul Brook <paul@codesourcery.com>
Cc: qemu-devel@nongnu.org, Gleb Natapov <gleb@redhat.com>

On Wed, Jul 29, 2009 at 9:18 PM, Filip Navara<filip.navara@gmail.com> wrote:
> On Wed, Jul 29, 2009 at 9:11 PM, Paul Brook<paul@codesourcery.com> wrote:
>>> Why shouldn't we support loading version 2 snapshots? Afterall that's
>>> why we had the versioning in the first place.
>>
>> No it's not. Versioning was introduced to *prevent* loading old snapshots and
>> crashing or ending up with inconsistent guest state. I'm still unconvinced
>> that anything other than very short term backward compatibility is worthwhile
>> or even viable.
>
> I see it as a way to migrate a running guest to newer QEMU version, possibly
> even with live migration. In fact I used it quite often back in the day when
> snapshots were not part of qcow2 yet and when kqemu was still in its heydays.
>

BTW, why would there be the version parameter in the first place if it
wasn't supposed to load older versions?!

Best regards,
Filip Navara