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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.

Section 3 – Configure and Administer vSphere 6.x Storage

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)
  • A
    90% (35)
  • B
    8% (3)
  • C
    3% (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.

ADirect access to the storage array deviceCorrect

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.

BVirtual Machine Snapshots

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.

CHardware Acceleration

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.

DGuest Clustering across ESXi hostsCorrect

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

Topics

#Raw Device Mapping#physical mode RDM#guest clustering#storage access

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