2V0-621 · 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 for scenarios that need raw SCSI command passthrough, specifically direct storage array access and guest OS-level clustering spanning multiple ESXi hosts.
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
(39 responses)- A90% (35)
- B8% (3)
- C3% (1)
Why each option
Physical Mode RDM is required for scenarios that need raw SCSI command passthrough, specifically direct storage array access and guest OS-level clustering spanning multiple ESXi hosts.
Physical Mode RDM passes SCSI commands directly to the LUN without virtualization, enabling the guest OS to directly access and control the storage array device, which is necessary for SAN management utilities and similar workloads running inside a VM.
Virtual Machine Snapshots are incompatible with Physical Mode RDM - snapshots require a Virtual Mode RDM or VMDK because Physical Mode RDM does not support the delta disk mechanism needed for snapshot creation.
Hardware Acceleration (VAAI) does not require Physical Mode RDM - VAAI offloads operations to the storage array and functions with standard VMDKs and Virtual Mode RDMs.
Guest clustering across ESXi hosts such as Microsoft Cluster Services requires Physical Mode RDM because cluster nodes need shared disk access at the raw SCSI level across different ESXi hosts, which only Physical Mode RDM enables.
Concept tested: Physical Mode RDM use cases and compatibility requirements
Source: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.storage.doc/GUID-9E2A1C7C-0B3A-4D2A-8B27-B36A8F77A3C4.html
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