Not able to find a LUN in the list to add as an RDM to a VM

Products

• VMware vCenter Server

Issue/Introduction

• The goal is to give direct access to a virtual machine to a raw LUN. In other words, an RDM is to be added to a LUN.
• The LUN to be added as an RDM is not seen on the listing of available LUNs when you follow the steps below to add the RDM:
  • Right-click the VM > Edit Settings> Add RDM disk.
• The LUN is well presented to the host, so it's well seen on Host > Configure > Storage devices.

Environment

VMware vSphere (All versions).

Cause

The common causes are that the target LUN is already being used for a VMFS datastore or as an RDM connected to another VM.

Only unformatted LUNs are to be displayed for your selection on "Right-click the VM > Edit Settings> Add RDM disk".

Resolution

Use only unformatted LUNs to be added as RDMs to virtual machines.

 

Note:

A LUN to be used as an RDM attached to a VM has to be used exclusively for this end.

Additional Information

• LUN filtering mechanism during RDM creation

• Add new RDM to existing Microsoft Windows Server Failover Clustering (WSFC) VMs