CPU & vCPU Clarification

[schirpich]

Just a simple question I'm not sure about, could use a little clarification.

I have a quad core server, proxmox 1.7 and 5 containers running on it. Each is set at 1 vcpu.

If each container is set at one vcpu, is it still using all 4 cores at the VZ server level? Or is the affinity for that container really set to only ever use a single core at the server level at any given moment?

And secondly, if I add more vcpu's to a container via the proxmox web interface, do I need to restart the container for the setting to actually take effect?

 

[dietmar]

If each container is set at one vcpu, is it still using all 4 cores at the VZ server level? Or is the affinity for that container really set to only ever use a single core at the server level at any given moment?

CPU limit only works with kernel 2.6.18

And secondly, if I add more vcpu's to a container via the proxmox web interface, do I need to restart the container for the setting to actually take effect?

Well, AFAIK setting are activated immediately for new tasks. But existing tasks are not affected.

 

[schirpich]

When you say kernel 2.6.18, am I understanding correctly that "only" kernel 2.6.18 or 2.6.18 and above?

I am currently running 2.6.32

And for the tasks, does this mean processes running on the container?

For instance If I don't set the MaxRequestsPerChild directive in apache, that particular process never dies and from what I understand would never see/use the newly added vcpu's unless it was killed or restarted?

 

[tom]

currently only our 2.6.18er kernel supports OpenVZ cpu limits. upcoming 2.6.32 kernels should also have this feature.