We are going to have 20 hosts and we are wondering - What is the best practice for hosts in a cluster? Is it best to put all 20 into one cluster? Would that hinder or help performance? Or is it best to split them into however many clusters we wish to create?
It actually depends on your needs. If the hardware is similar and there are no requirements to create multiple clusters, I'd probably go with a single cluster to have all the benefits, i.e. load balancing, toleration of HA failures, ...
André