2V0-622 · Question #67
Which two solutions require Physical Mode Raw Device Mapping (RDM)? (Choose two.)
The correct answer is A. Direct access to the storage array device D. Guest Clustering across ESXi hosts. Physical Mode RDM is required specifically when the guest OS needs raw SCSI command access to the LUN, such as for direct array access or inter-host guest clustering.
Question
Which two solutions require Physical Mode Raw Device Mapping (RDM)? (Choose two.)
Options
- ADirect access to the storage array device
- BVirtual Machine Snapshots
- CHardware Acceleration
- DGuest Clustering across ESXi hosts
How the community answered
(30 responses)- A93% (28)
- B3% (1)
- C3% (1)
Why each option
Physical Mode RDM is required specifically when the guest OS needs raw SCSI command access to the LUN, such as for direct array access or inter-host guest clustering.
Physical Mode RDM passes SCSI commands directly from the guest OS to the storage device with minimal hypervisor intervention, which is necessary when applications need direct low-level access to the storage array.
Virtual Machine Snapshots are not supported with Physical Mode RDM - snapshots require virtual disk files (VMDK) or Virtual Mode RDM, making pRDM incompatible with this feature.
Hardware Acceleration (VAAI) offloads operations like clone, zeroing, and locking to the array and works with standard VMDK or Virtual Mode RDM - it does not require Physical Mode RDM.
Guest OS clustering across ESXi hosts (such as Microsoft Clustering Services spanning multiple hosts) requires Physical Mode RDM because the cluster nodes need to issue persistent SCSI reservations directly to the shared LUN, which only pRDM supports.
Concept tested: Physical Mode RDM use cases and requirements
Source: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.storage.doc/GUID-9E6191B3-7E36-46D0-8316-D9B07A3E67F4.html
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