Previously, we have described the scope of a vSAN fault domain and the possibility to define explicit fault domains, usually needed for rack/enclosure awareness or mandatory for vSAN stretched cluster configuration (in this case, each site is a fault domain).
You can configure fault domains during the vSAN creation, but also later. Using the vSphere Web Client, select the vSAN cluster in the Hosts and Clusters inventory. In the Configure tab, choose the vSAN | Fault Domains & Stretched Cluster menu:
Note that, depending on the configuration of the host, you have different ...