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Re: [PATCH v2 01/27] migration: Network Failover can't work with a pause
From: |
Michael S. Tsirkin |
Subject: |
Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest |
Date: |
Wed, 2 Dec 2020 05:31:50 -0500 |
On Wed, Dec 02, 2020 at 10:27:18AM +0000, Daniel P. Berrangé wrote:
> On Wed, Dec 02, 2020 at 05:13:18AM -0500, Michael S. Tsirkin wrote:
> > On Wed, Nov 18, 2020 at 09:37:22AM +0100, Juan Quintela wrote:
> > > If we have a paused guest, it can't unplug the network VF device, so
> > > we wait there forever. Just change the code to give one error on that
> > > case.
> > >
> > > Signed-off-by: Juan Quintela <quintela@redhat.com>
> >
> > It's certainly possible but it's management that created
> > this situation after all - why do we bother to enforce
> > a policy? It is possible that management will unpause immediately
> > afterwards and everything will proceed smoothly.
> >
> > Yes migration will not happen until guest is
> > unpaused but the same it true of e.g. a guest that is stuck
> > because of a bug.
>
> That's pretty different behaviour from how migration normally handles
> a paused guest, which is that it is guaranteed to complete the migration
> in as short a time as network bandwidth allows.
>
> Just ignoring the situation I think will lead to surprise apps / admins,
> because the person/entity invoking the migration is not likely to have
> checked wether this particular guest uses net failover or not before
> invoking - they'll just be expecting a paused migration to run fast and
> be guaranteed to complete.
>
> Regards,
> Daniel
Okay I guess. But then shouldn't we handle the reverse situation too:
pausing guest after migration started but before device was
unplugged?
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- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Michael S. Tsirkin, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Daniel P . Berrangé, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest,
Michael S. Tsirkin <=
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Michael S. Tsirkin, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Juan Quintela, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Daniel P . Berrangé, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Michael S. Tsirkin, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Daniel P . Berrangé, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Michael S. Tsirkin, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Daniel P . Berrangé, 2020/12/02
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Michael S. Tsirkin, 2020/12/03
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Daniel P . Berrangé, 2020/12/03
- Re: [PATCH v2 01/27] migration: Network Failover can't work with a paused guest, Michael S. Tsirkin, 2020/12/03