Assign all the CPU cores to a single VM
-
What is the maximum amount of cores that can be assigned to a VM?
I know the max limit known is 32 but can I make it more?
For example - if we buy 2 x CPUs that have 32 cores like AMD EPYC. Is there a way to override the limit so i can assign all the 64 cores to the VM? or even better all the 128 threads to the VM ?
-
Hi,
The main limit is that you can't assign more vCPUs than physical cores on a machine (for obvious security reasons since Spectre/Meltdown)
The other one is that after 64 cores, there's no official support. However, it might work OK on Linux, for Windows I have no idea.
-
alright i managed to put my hands on such host.
out of 128 cores (including hyperthreading) i managed to create a Debian 11 vm with 108 cores. if i go higher i get an error.
I assume the error is due to some threads being exclusive for the hypervisor. Its possible that is the actual limit too though.
Not that important though just got curious how far i can push it.
-
What kind of error do you have?
-
@olivierlambert its looks like it was not from XCP but from the cloud provider managing it (Cloudstack). as soon as max restrictions were removed i could assign all 128 threads as vCPUs to a single VM.
-
D dredknight marked this topic as a question on
-
D dredknight marked this topic as a regular topic on
