Understanding CPU Masking

mauzilla

We want to add a new member to our pool (existing Dell range). Logically I want to add a newer "range" to the pool, but my understanding is that the pool will mask CPU features to whatever the lowest CPU member is in the pool. Given that the other hosts are a generation older, does this then mean the newer generation CPU would effectively be "watered down" to match that of the rest of the pool?

Likewise, adding an older generation to the pool would have the same affect, moving the entire rest of the pool to the lowest denominator?

bleader

ping @Team-Hypervisor-Kernel

olivierlambert

Hi,

Yes, by default, adding a new host to a pool, it will be lowered on CPU features to the common denominator, in other word, cutting that's not common between all pool members.

So:

If you add a more recent CPU to an existing pool, the CPU won't use new CPU features
If you add an older host to a pool, it will lower down all features from existing CPUs