The ways of accessing a SCSI-based storage device include a virtual disk file on a VMFS datastore, virtual mode RDM, and physical mode RDM.
To help you choose among the available access modes for SCSI devices, the following table provides a quick comparison of features available with the different modes.
|ESXi Features||Virtual Disk File||Virtual Mode RDM||Physical Mode RDM|
|SCSI Commands Passed Through||No||No||
REPORT LUNs is not passed through
|vCenter Server Support||Yes||Yes||Yes|
| Physical-to-virtual clustering
|SCSI Target-Based Software||No||No||Yes|
VMware recommends that you use virtual disk files for the cluster-in-a-box type of clustering. If you plan to reconfigure your cluster-in-a-box clusters as cluster-across-boxes clusters, use virtual mode RDMs for the cluster-in-a-box clusters.