Once the total CPU and memory resource requirements have been calculated, the amount of resources per host must be determined. Host resources can be designed based on two resource-scaling methodologies, scaling up or scaling out.
When scaling up, fewer, larger hosts are used to satisfy the resource requirements. More virtual machines run on a single host; because of this, more virtual machines are affected by a host failure.
When scaling out, many smaller hosts are used to satisfy the resource requirements. Fewer virtual machines run on a single host, and fewer virtual machines will be affected by a host failure.
Determine whether the host in the environment should scale up or scale out.
Determine the number of virtual machine workloads per host.
Based on the number of virtual machines per host, calculate the number of hosts required. This should also include the number of hosts required to support growth and failover:
(Number of Workloads / Number of Workloads...
