Practical quorum guidance

It is recommended to allow the wizard to decide how to set your quorum.

For an even-node cluster, your first choice for a witness should be a cluster disk. They are commonly placed on the same physical storage as the guest machines, so it's a reasonable way to protect the cluster if it's not reachable. The virtual machine storage is likely to be unavailable as well, so it's of little consequence whether or not the cluster continues to operate.

For a file share witness to be truly useful, it should not be in a location that any cluster resource depends on. This means that it should not be on the shared storage for the cluster or any virtual machine. The file share witness is most useful in multicluster and multisite configurations. If you have a number of clusters, all of their witnesses can reside on a single file server that isn't part of any of them. For a multisite cluster, the benefit of a file share witness is that it does not require a single iSCSI or Fibre...