More virtual than physical cpus

[mgiammarco]

Hello,
Imagine this, I have some servers with 16 cores each and one emergency server with 4 cores.
I migrate an 8 vcpus machine to the emergency server but proxmox stops me because the virtual machine has more cores than the server.
I think the virtual machine can run, albeit at reduced performance but there are no real problems to run it anyway on the emergency server.
How can I do it in proxmox?

Thanks,
Mario

 

[t.lamprecht]

The problem here is that when running on a cpu with less cores that vcpu cores all of the virtual cores get emulated (not only some), and that's really really slow. Don't know how useable your system is with that.

It's currently hardcoded that the VM mus have the same or less vcpus, so no easy workaround.

You could patch the file/package yourself if really necessary but it's a bit an ugly way, for the sake of completnes here is the file, it's on line 2827: https://git.proxmox.com/?p=qemu-ser...8257aa408f43b251e35d5bb19933ecf;hb=HEAD#l2815