The following figure shows a campus cluster configuration with Microsoft clustering. It features mirrored storage across clusters and a mirrored quorum resource. The figure shows a four-way mirrored quorum that has an extra set of mirrors for added redundancy. Although a campus cluster setup with Microsoft clustering can work without Storage Foundation, SFW provides key advantages over using Microsoft clustering alone. Through a dynamic mirrored volume that functions on multiple disks across multiple sites, SFW protects the quorum resource in the cluster from being the single point of failure in the cluster.

Most customers use hardware RAID to protect the quorum disk, but that will not work when a natural disaster takes down the primary node and its attached storage. If the quorum resource is lost to the cluster, the cluster fails, because none of the cluster servers can gain control of the quorum resource and ultimately the cluster. Microsoft clustering alone cannot provide fault tolerance to the quorum disk.