Requirements for vSAN over physical VXLAN underlay in multi-rack deployments

Products

• VMware vSAN

Issue/Introduction

This article provides technical guidance on deploying vSAN across multiple racks using a physical VXLAN underlay (Layer 2) as well as the integration of VMware NSX with vSAN.

• In multi-rack or leaf-spine architectures, administrators may use VXLAN at the physical switch layer (underlay) to stretch vSAN VLANs across racks.
• While vSAN is compatible with physical VXLAN encapsulation provided by hardware vendors, there are architectural boundaries regarding NSX-managed overlays.

Environment

VMware vSAN 8.x

VMware vSAN 9.x

 

Cause

VMkernel traffic is not supported over the NSX-managed VXLAN overlay is to avoid any circular dependency between the VMkernel networks and the VXLAN overlay that they support. The logical networks delivered with the NSX-managed VXLAN overlay are used by virtual machines, which require network mobility and flexibility.

Resolution

• Engage the network team to validate the underlying switch configuration for VTEP (VXLAN Tunnel Endpoint) and loopback interfaces are configured correctly to maintain 0% packet loss for encapsulated vSAN traffic.
  
  
• Ensure that the MTU size is consistently configured across:

• •     The Physical Switch Fabric (Spine and Leaf layers).
  •     The vSAN Distributed Virtual Switch (vDS).
  •     The vSAN VMkernel adapters.

Reference the documentation for Using VMware NSX with vSAN.

Additional Information

Reference the documentation for vSAN Networking Requirements guide.