If you deploy VxRail stretched clusters instead of a single-site cluster in order to meet availability requirements, be aware of the impact this decision has in planning the workload. A VxRail stretched cluster requires double the number of VxRail nodes to support any planned workload, as each site must be able to support that workload in the event of a site failure.
Figure 18. Impact of VxRail stretched cluster on virtual machine workload
In addition, every write operation by a virtual machine is performed on the vSAN datastore at both sites. Therefore, the size of the physical storage positioned to support any planned workload must be doubled.