On Thu, Dec 06, 2018 at 10:01:46AM +0000, Daniel P. Berrangé wrote: > Users absolutely *do* care why migration is not finishing. A migration that > does not finish is a major problem for mgmt apps in many case of the use > cases for migration. Especially important when evacuating VMs from a host > in order to do a software upgrade or replace faulty hardware. As mentioned > previously, they will also often serialize migrations to prevent eh network > being overutilized, so a migration that runs indefinitely will stall > evacuation of additional VMs too. Predictable execution of migration and > clear error reporting/handling are critical features. IMHO this is the key > reason VFIO unplug/plug needs to be done explicitly by the mgmt app, so it > can be in control over when each part of the process takes place.
On Fri, Apr 05, 2019 at 09:56:29AM +0100, Dr. David Alan Gilbert wrote: > Why not just let this happen at the libvirt level; then you do the > hotunplug etc before you actually tell qemu anything about starting a > migration? On Thu, May 30, 2019 at 07:00:23PM +0100, Dr. David Alan Gilbert wrote: > Well no, we need to know this thing isn't going to hang in the migration > setup phase, or if it does how we recover. This patch series is very > odd precisely because it's trying to do the unplug itself in the > migration phase rather than let the management layer do it - so unless > it's nailed down how to make sure that's really really bullet proof > then we've got to go back and ask the question about whether we should > really fix it so it can be done by the management layer. > I have the impression we are running in circles here. -- Eduardo
