vSAN stretched-cluster is a VMware solution that supports synchronous I/O on a vSAN datastore over distance and is supported on VxRail. A vSAN stretched-cluster enables site-level failure protection with no loss of service or loss of data.
If you plan to deploy a vSAN stretched-cluster on VxRail, note the following requirements:
The vSAN stretched-cluster feature has strict networking guidelines, specifically for the WAN, that must be adhered to for the solution to work.
Figure 11 vSAN Stretched Cluster Topology
More detailed information about vSAN stretched-cluster and the networking requirements can be found in the Dell-EMC VxRail vSAN Stretched Cluster Planning Guide.