vSphere supports the use of VMDKs on clustered datastore as shared disk resources for a WSFC. Using VMDKs reduces the extra overhead to manage the virtual disks compared to pRDMs.
Microsoft Clustering Service uses SCSI-3 PRs commands to coordinate access to a clustered disk resource. These commands (PR-IN and PR-Out) are emulated at VSCSI layer on a datastore. The feature requires support from the datastore perspective. A datastore configured to host clustered VMDKs is referred to as a clustered VMDK datastore in this document.