In this case you can size the ESXi hosts by considering the total required CPU and the total required RAM, define which growth margin you would like to plan (or which is required by business goals), and preserve a part for the high availability aspects (as we will discuss in Chapter 13, Advanced Availability in vSphere 6.5), considering not only vSphere HA, but also vSphere Fault Tolerance (FT) (if used). With the numbers, you can define a building block (or use a vendor predefined building block, like a Nutanix or vSAN ready node) for the single ESXi host and find out how many blocks are needed to reach the required CPU or RAM amount.
For the hosts, you can use different types of approaches for cluster design:
- Scale-out: More ...
