Best CPU type to use

[Hollow]

Hello,

I am working on installing PVE to a cluster of 4 identical servers (CPU, Memory, Disks, etc..) and wondering which would be the best CPU type to use and why. I see that kvm64 is the default choice that Proxmox has set but I have read that Host is good however it can cause live migration issues. The other option I see is to use Max which sets the CPU to be the highest supported level. What would be the best CPU Type to use and why? For the future I will be adding more identical servers to the cluster.

Thanks for the help!

 

[VictorSTS]

If all your CPUs are the same brand and model/series just use "host". It does work perfectly well for live migration.

The issues related to CPU type and live migration are related to using different CPUs on your hosts. Newer CPUs have instruction sets that older CPUs do not have, so if you live migrate a VM from a newer CPU to an older one, the VM will hang/fail/misbehave at some point, maybe just after the migration or some time later. Live migrating from an older CPU to a newer one has a higher chance of success. Things get harder when you realize that even different steppings or microcode versions may affect live migration functionality.

 

[Zaf9670]

I saw somewhere that certain AMD chips like the earlier Ryzen and Threadripper actually have some issue with the host option. So your mileage can vary per CPU.
I think I'm going to try to see what my common instructions are per CPU in my available hardware to make a generic custom CPU listing. Just to see how well it works versus host maybe.