Sizing the vSAN volume can be approached in several ways, depending on the factors that are most important to the environment. All different policy settings can impact the available space in the cluster. Also, the resultant sizing can mean additional hardware is required or that disk groups must be configured in a specific way.

To reduce complexities when estimating the size of the vSAN configuration, VMware released the VMware vSAN TCO and Sizing tool (https://vsantco.vmware.com/). To use the tool, simply enter the parameters. The calculator will generate the optimal configuration.

The following figure shows the results of a typical sizing recommendation from the tool.

 

VMware recommends using the vSAN Sizing tool to determine the correct number of hosts and sizing for the cluster. For proper recoverability, use eight or more hosts in the cluster to support the configured fault domains. The end datastore size and number of hosts is dependent on the end workloads being hosted on vSAN, and it must be sized accordingly. Therefore, before selecting a drive size, consider disk groups, sizing, and expected future growth.