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Re: [Qemu-devel] migrating instances from qemu-kvm to qemu
From: |
Serge E. Hallyn |
Subject: |
Re: [Qemu-devel] migrating instances from qemu-kvm to qemu |
Date: |
Wed, 19 Mar 2014 16:52:16 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Quoting Paolo Bonzini (address@hidden):
> Il 19/03/2014 16:42, Serge E. Hallyn ha scritto:
> >Hi,
> >
> >at https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1291321
> >it was found that migrating running vms from a machine with
> >qemu-kvm to one with qemu, migration fails due to some mismatches.
> >The first one we usually hit is
> >
> >Length mismatch: vga.vram: 1000000 in != 800000
> >
> >while the second one is network card (and I have not gone beyond
> >that).
>
> This is just a different default. Make sure you specify the right
> model on the command line.
>
> >The vga one can be handled on the command line by
> >specifying the -global cirrus-vga.vrammem_mb=8. However that
> >doesn't help with a libvirt migration.
>
> You can patch Ubuntu's QEMU to detect old machine types (pc-1.2 and
> earlier) and give cirrus-vga 16MB memory by default. Migration only
> works with versioned machine types (or between same-version QEMU),
> so it's okay to only do it there.
>
> >I guess this happens at ram_load() unfortunately - is there any
> >good way that this could be detected at incoming migration time
> >and the virtual hardware modified as needed for migration to
> >continue?
>
> It cannot, but the destination can be patched to operate correctly
> for the old machine types, on the assumption that migration from the
> old machine types is always from Ubuntu's qemu-kvm.
>
> Paolo
Ah, thank you, that assumption should be safe and sounds like a
great idea.
thanks,
-serge
- [Qemu-devel] migrating instances from qemu-kvm to qemu, Serge E. Hallyn, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Paolo Bonzini, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu,
Serge E. Hallyn <=
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Serge E. Hallyn, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Paolo Bonzini, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Dr. David Alan Gilbert, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Serge E. Hallyn, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Dr. David Alan Gilbert, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Paolo Bonzini, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Cole Robinson, 2014/03/19
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Serge E. Hallyn, 2014/03/21
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Cole Robinson, 2014/03/21
- Re: [Qemu-devel] migrating instances from qemu-kvm to qemu, Serge E. Hallyn, 2014/03/21