AMD EPYC and Intel Xeon CPU's in Same Cluster - Migration?

[JakeBikeIT]

Hi All,

I want to build VM's in a cluster that will have one powerful EPYC machine and other not so powerful Xeon machines supporting other roles.
Not ideal - but its what we have.

Can I use the emulated "stock KVM" CPU's to facilitate live migration?

TBH Failover in case of hardware failure is my real target.

 

[VictorSTS]

Live migration probably won't work. I'm still to test with new PVE8 custom cpu model x86-64-v2-AES, which have worked quite nicely on mixed generation Intel clusters I have. Currently I no mixed AMD/Intel clusters to test.

Anyway, if you only want to cover failover if you Epyc host go south, you can use "host" type CPU, as when the failover happens, the VM will be off already, so no live migration will happen.

 

[pvps1]

Hi All,

I want to build VM's in a cluster that will have one powerful EPYC machine and other not so powerful Xeon machines supporting other roles.
Not ideal - but its what we have.

Can I use the emulated "stock KVM" CPU's to facilitate live migration?

TBH Failover in case of hardware failure is my real target.

in our experience, no.
we switched from intel to amd some years ago and nearly 100% of live migrations between different archs ended in segfaults.

 

[fiona]

Hi,
please see the CPU Type section in the documentation: https://pve.proxmox.com/pve-docs/chapter-qm.html#qm_cpu

In short:

If you don’t care about live migration or have a homogeneous cluster where allnodes have the same CPU and same microcode version, set the CPU type to host, asin theory this will give your guests maximum performance.

If you care about live migration and security, and you have only Intel CPUs oronly AMD CPUs, choose the lowest generation CPU model of your cluster.

If you care about live migration without security, or have mixed Intel/AMDcluster, choose the lowest compatible virtual QEMU CPU type.

Live migrations between Intel and AMD host CPUs have no guarantee to work.