The cluster design must take into account the workload that the cluster must handle.
vSphere Cluster Design Decision Background
The following heuristics help with cluster design decisions.
Decide to use fewer, larger hosts or more, smaller hosts.
A scale-up cluster has fewer, larger hosts.
A scale-out cluster has more, smaller hosts.
A virtualized server cluster typically has more hosts with fewer virtual machines per host.
Compare the capital costs of purchasing fewer, larger hosts with the costs of purchasing more, smaller hosts. Costs vary between vendors and models.
Evaluate the operational costs of managing a few hosts with the costs of managing more hosts.
Consider the purpose of the cluster.
Consider the total number of hosts and cluster limits.