It might be desirable to span WLD clusters across racks to avoid a single point of failure within one rack. The management VMs running on the Mgmt WLD cluster and any management VMs running on the VI WLD require VxRail nodes to reside on the same L2 management network, so that the VMs can be migrated between racks and maintain the same IP address. For a Layer 3 Leaf-Spine fabric, this is a problem as the VLANs are terminated at the leaf switches in each rack.
VxRail multi-rack cluster is a network design that allows a single (or multiple) VxRail clusters to span between racks. This particular solution uses a Dell EMC PowerSwitch hardware VTEP to provide an L2 overlay network to extend L2 segments over an L3 underlay network for VxRail node discovery, vSAN, vMotion, management, and VM/App L2 network connectivity between racks. The following diagram is an example of a multi-rack solution using hardware VTEP with VXLAN BGP EVPN. The advantage of VXLAN BGP EVPN over static VXLAN configuration is that each VTEP is automatically learned as a member of a virtual network from the EVPN routes received from the remote VTEP.