[PVE-User] Move VMs / local storage to new host with minimal downtime

[Fabian Grünbichler]

On Tue, Feb 14, 2017 at 12:09:44AM +0100, Kevin Lemonnier wrote:
> > So I need to create the VM on the new host and then attach the moved disk – is there any doc about ? I guess I also should copy the configuration file.
> 
> Yeah, I usually just re-create it before hand, move disk them plan a little downtime to shut it down on the old hypervisor
> and power it up on the new later. You don't have to do both at the same time.
> 
> As for attaching the disk, you can't. What you need to do is create the VM with an identical disk and the same ID, then rm that disk
> by hand on the filesystem, then move the disk from the other hypervisor on that storage : it'll get the same path as the one
> you removed.
> That's a ridiculous way to do it, but unfortunatly proxmox still doesn't have an attach existing disk button, that's the best
> I came up with.

"qm rescan -vmid ID" will scan for non-referenced disks for the given
VMID on all configured storages on the local node and add them as
unused. you just need to make sure that they follow the expected naming
scheme for that storage.

> 
> If you can afford a bit more downtime you can always just mv the disk on top of the empty one, that'll work too, but I'm
> always afraid I'll mess up and overwrite the "real" one with the empty one ..
>