Unable to map RDM disk to WFSC clustered VM failed with an error "Cannot open the disk ###.vmdk' or one of the snapshot disks it depends on"

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms : 

While attaching RDM disk to the VM received below error in UI. 

Reconfigure virtual machine,Reconfiguring Virtual Machine on destination host, UAT-####-.adm@tcsecp,###.##.COM,Failed to add disk scsi1:0.
File system specific implementation of Ioctl[file] failed
File system specific implementation of OpenFile[file] failed
File system specific implementation of OpenFile[file] failed
File system specific implementation of OpenFile[file] failed
File system specific implementation of OpenFile[file] failed
File system specific implementation of OpenFile[file] failed
File system specific implementation of OpenFile[file] failed
Failed to lock the file
Cannot open the disk '/vmfs/volumes/###-d91bd3##-###-0025b####/UAT-#####-2/UAT-#####-2_1.vmdk' or one of the snapshot disks it depends on.
Failed to power on scsi1:0.,6 ms,06/21/2025, 9:46:30 PM,06/21/2025, 9:46:56 PM,26 s

The VMs are part of WFSC clustering.  

The RDM disks are attached for Primary and Secondary VMs. While adding the RDM disk to secondary VM it was attached as New hard disk 

 

Environment

VMware vSphere ESXI 8.x 

Cause

The virtual machine clustering setup does not follow Broadcom's best practices for shared disks in a WSFC environment. This misconfiguration can lead to file lock issues, especially during operations like failover. 

Cause Validation 

The SCSI bus sharing setting is configured to None on the SCSI controller which is used for Clustering VMs which is incompatible with shared disk access.

Resolution

Power off secondary VM in the WFSC cluster.

On both VMs (Primary and Secondary) set the SCSI controller’s bus sharing mode to Physical.

Remove the previously added shared hard disks from the secondary VM.

Re-add the shared disks to the secondary VM using the “Existing Hard Disk” option, pointing to the same VMDK or RDM pointer file used by the primary VM

Follow Best Practices mentioned in KB : 313230