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[Qemu-devel] Re: Live migration protocol, device features, ABIs and othe
From: |
Michael S. Tsirkin |
Subject: |
[Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts |
Date: |
Tue, 24 Nov 2009 15:55:15 +0200 |
User-agent: |
Mutt/1.5.19 (2009-01-05) |
On Tue, Nov 24, 2009 at 07:45:13AM -0600, Anthony Liguori wrote:
> Michael S. Tsirkin wrote:
>> On Sun, Nov 22, 2009 at 09:49:26AM -0600, Anthony Liguori wrote:
>>
>>>> We cannot even create a new 'hack section' for new code since the
>>>> sections are ordered and expected to be exact match on the
>>>> destination.
>>>>
>>>> The result is that new->old migration cannot work. This is not cross
>>>> releases even! It means that even a small bug in current release
>>>> prevents live migration between various instances of the code.
>>>> It forces us to decide whether to fix pvclock migration issue vs
>>>> allow new->old migration. Another ugly hack is to add cmdline that
>>>> will control this behavior. Still it's a pain to mgmt stack and
>>>> users.
>>>>
>>> This is a pretty normal policy (backwards compat but not forwards compat).
>>>
>>
>> No one is asking that old qemu magically understands new format. It
>> would be enough that new qemu is able to migrate to a format that old
>> one understands.
>>
>
> I've got no problem with that provided it's something explicitly
> requested by the user. This requires no migration protocol change
> though so if this is what folks are asking for, why is this thread
> focused around changing the live migration protocol?
I think the claim is that a section-based migration
protocol would make implementing this easier than
version-based one, especially for downstream which might
cherry-pick a feature from a new release to an old one.
It seems the requirement discussion and the implementation
discussion are going on together in this thread.
> Regards,
>
> Anthony Liguori
>
>
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, (continued)
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Paolo Bonzini, 2009/11/24
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Anthony Liguori, 2009/11/24
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Blue Swirl, 2009/11/24
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Anthony Liguori, 2009/11/24
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Paolo Bonzini, 2009/11/24
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Anthony Liguori, 2009/11/24
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Michael S. Tsirkin, 2009/11/24
- Message not available
- [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Paolo Bonzini, 2009/11/24
[Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Michael S. Tsirkin, 2009/11/24
[Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Juan Quintela, 2009/11/23
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Anthony Liguori, 2009/11/23
- [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Juan Quintela, 2009/11/23
- [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Michael S. Tsirkin, 2009/11/24
- [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Juan Quintela, 2009/11/24
- [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Michael S. Tsirkin, 2009/11/24
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Gerd Hoffmann, 2009/11/25
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Michael S. Tsirkin, 2009/11/25
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Gerd Hoffmann, 2009/11/25
- Re: [Qemu-devel] Re: Live migration protocol, device features, ABIs and other beasts, Michael S. Tsirkin, 2009/11/25