Different physical CPUs in one cluster: VM CPU speed unchanged after live migration


Renowned Member
Apr 18, 2015
The Netherlands
We had 5 exactly the same physical nodes for our PVE 4.4 cluster. Now we needed to expand our capacity, so we bought 2 more servers, but this new servers aren't the same as the first servers. All 7 servers have dual Intel Xeon CPU's, but different models. Clockspeed of the first servers is 2,67GHz per CPU, clockspeed of the 2 latest servers is 2,50GHz per CPU.

All VM's have "kvm64" as CPU type. Live migration is working between "old" and "new" nodes. But it came to my attention that when a VM is migrated from a 2,67GHz node to a 2,50GHz node, the VM clockspeed stays at 2,67GHz, while it's host only have 2,50GHz! How is this possible and is this fixable? Something like a "resync" of the CPU clockspeed after the VM is migrated? VM (guest) OS is Debian 8.


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