[pve-devel] [PATCH v4 qemu-server 2/2] remote-migration: add target-cpu && target-reboot params

DERUMIER, Alexandre alexandre.derumier at groupe-cyllene.com
Tue Oct 10 18:29:06 CEST 2023

> I think that a true offline migration (without starting any
> source/target vm) can be done with qemu-storage-daemon running nbd
> server on target &&  qemu-img on source.
> This could be also used for online migration with unused/detached
> disks.

>>Yes, we could, but would require additional logic. So the question is
>>there are enough advantages to do it rather than via a full VM.
>>a VM of course requires more resources.

I don't known if it's possible to use the ndb server in the targetvm,
if the target disk is not attached ? (I really don't known)

>>In case of 'restart' migration, we do want to start the VM anyways,
>>it's actually better, because we can catch config issues early :) Now
>>that I think about it, can we also just start the target VM in
>>mode (instead of incoming migration mode), do the NBD migration, shut
>>down the source VM, stop the NBD server and then resume the target?
>>would avoid the need to stop and start the target again. And
>>might be quite a bit less downtime.

Yes, indeed ! I'll work on this for next version.

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