Introduced in VCF version 4.2, vSAN HCI Mesh supports the sharing of spare vSAN storage capacity between VxRail clusters in a VI WLD. It can only be used as a secondary storage option; either vSAN or FC storage must be used for primary storage. vSAN HCI Mesh enables an alternative method to alleviate decreasing storage capacity in a VI WLD. This alternative can be useful for environments that are not compute-constrained in a VI WLD to avoid adding nodes, which increase both compute and storage resources.

The following prerequisites must be met before configuring vSAN HCI Mesh:

• All VxRail clusters participating in an HCI mesh topology must be managed by a single vCenter instance.
• All VxRail clusters participating in an HCI mesh topology located under a single data center instance.
• Data center network configured to enable connectivity between server VxRail cluster and client VxRail cluster.
• The client VxRail cluster can mount no more than five remote vSAN datastores from server VxRail clusters.

The server VxRail cluster’s vSAN datastore is not mounted by more than five client VxRail clusters.

The configuration of the client and server VxRail clusters in a vSAN HCI mesh is performed in the VxRail cluster level using the vClient. SDDC manager detects the presence of a vSAN HCI Mesh in a VI WLD and alerts the user through SDDC Manager. All existing VCF on VxRail workflows are compatible with vSAN HCI mesh. SDDC Manager has integrated constraints to prevent the removal of a dependent VI WLD or dependent VxRail cluster if there is a sharing of a vSAN datastore in effect.