[ovirt-users] [Qemu-block] Enabling libgfapi disk access with oVirt 4.2

[Kevin Wolf]

Am 15.11.2017 um 23:05 hat Nir Soffer geschrieben:
> On Wed, Nov 15, 2017 at 8:58 AM Misak Khachatryan <kmisak at gmail.com> wrote:
> 
> > Hi,
> >
> > will it be a more clean approach? I can't tolerate full stop of all
> > VMs just to enable it, seems too disastrous for real production
> > environment. Will it be some migration mechanisms in future?
> >
> 
> You can enable it per vm, you don't need to stop all of them. But I think
> we do not support upgrading a machine with running vms, so upgrading
> requires:
> 
> 1. migrating vms from the host you want to upgrade
> 2. upgrading the host
> 3. stopping the vm you want to upgrade to libgfapi
> 4. starting this vm on the upgraded host
> 
> Theoretically qemu could switch from one disk to another, but I'm not
> sure this is supported when switching to the same disk using different
> transports. I know it is not supported now to mirror a network drive to
> another network drive.

I don't think this is possible yet, but we're relatively close to
actually allowing this. No promises as to when qemu will allow QMP to
make arbitrary changes to the block graph, but it is being worked on.

Kevin