VMFS Datastore Inaccessible and VMs Orphaned Due to Windows ReFS Reformat

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms: 

• A VMFS datastore suddenly loses its VMFS metadata and directory structure.
• Virtual machines residing on this datastore transition to an "Orphaned" or "Inaccessible" state in the vCenter Server inventory.
• Storage analysis reveals that the original VMFS partition table is missing and has been replaced by a GUID Partition Table (GPT) containing a Windows ReFS file system signature.
• Other LUNs within the same storage fabric remain healthy.
• partedUtil shows no VMFS partition 

Environment

VMware vSphere ESXi 8.x 
VMware vSphere ESX  9.0, 9.0.1, 9.0.2, 9.1

Cause

• The storage LUN backing the VMFS datastore was incorrectly presented to a Windows host, and reformatted the volume with the Windows ReFS file system.
• A hexdump of the device confirms that the VMFS partition table, LVM headers, and VMFS signatures have been overwritten by ReFS offsets, destroying the VMFS structural integrity.

hexdump output: 

Resolution

• This datastore can't be recovered with manual efforts.
• This needs to be restored from backup or involved recovery vendor for software based recovery.