Clustering Configuration Overview

Several applications use clustering, including stateless applications such as Web servers, and applications with built-in recovery features such as database servers. You can set up WSFC clusters in several configurations, depending on your environment.

A typical clustering setup includes:

• Disks resources that are shared between nodes. A shared disk is required as a quorum disk. In a cluster of virtual machines across physical hosts, shared disks can be RDMs, vVol or VMFS VMDKs. If you are using RDMs or vVol as shared disks, they can accessed using Fibre Channel (FC) SAN, FCoE or iSCSI. If you are using VMFS VMDKs as shared disks, only FC SAN connected storage devices are supported. A WSFC must have a homogenous set of disks. This means that if the configuration is done with disks attached using FC SAN, then all of the cluster disks should be FC SAN only. Mixed mode is not supported.

In ESXi 7.0, clustered VMDKs on VMFS datastores are supported in configurations when the VMs hosting the nodes of a cluster are located on different ESXi hosts, known as cluster-across-boxes (CAB) configuration.

Note: VMDKs in this guide refers to Shared disk files from VMFS datastore shared in physical compatibility mode (Attached to SCSI controller with bus sharing mode set to Physical) for cluster across physical machines. This is also known as Clustered VMDKs.