Newly presented LUNs report 0 MB capacity in vSphere

Products

• VMware vCenter Server 8.0
• VMware vSphere ESXi 8.0

Issue/Introduction

• One or more LUNs are mapped from storage array to an ESXi host.
• In vSphere Client, Under Device Backing, LUNs are seen but the size is shown as 0 MB
• To navigate to "Device Backing" :

Select the "Datastore" in question -->> Configure -->> Device Backing

 

Environment

VMware vSphere ESXi 8.0 
VMware vCenter Server 8.0

Cause

• This occurs when a LUN has previously been detached from a host and subsequently is re-presented to that same host. A detached LUN remains in detached state when re-presented to a host.
• Vobd.log, shows below errors:

2025-12-18T20:24:51.782Z In(14) vobd[2098917]: [scsiCorrelator] 9616992499112us: [vob.scsi.device.state.off] Device naa.####################### has been turned off administratively.
2025-12-18T20:24:51.782Z In(14) vobd[2098917]: [scsiCorrelator] 9616674259385us: [esx.problem.scsi.device.state.off] Device: naa.####################### has been turned off administratively
VMkernel.log shows below errors:

2025-12-30T10:07:18.135Z In(182) vmkernel: cpu204:2099029)ScsiDevice: 4882: Failed to register for 'REPORTED LUNS DATA CHANGED' unit attention for device:naa.#######################. Reason: Not found
2025-12-30T10:07:18.135Z In(182) vmkernel: cpu204:2099029)ScsiDevice: 4893: Failed to register for 'MODE PARAMETERS CHANGED' unit attention for device:naa.#######################. Reason: Not found
2025-12-30T10:07:18.135Z In(182) vmkernel: cpu204:2099029)ScsiDevice: 4904: Failed to register for 'CAPACITY DATA HAS CHANGED' unit attention for device:naa.#######################. Reason: Not found
2025-12-30T10:07:18.135Z In(182) vmkernel: cpu204:2099029)ScsiDevice: 4915: Failed to register for 'ASYMMETRIC ACCESS STATE CHANGED' unit attention for device:naa.#######################. Reason: Not found

 

Resolution

• To reattach the LUN from  the direct Host Client:

         Host  ---> Configure --> Storage Devices --> Select the correct backing device naa id --> Attach.

• Alternatively, can reattach the LUN by executing the following esxcli command on each affected ESXi host.
  esxcli storage core device set --state=on -d naa.#########################
   
• Post running the above command the Devices capacity should be shown correctly.

Additional Information

Incorrect LUN capacity information may prevent creation of a new datastore.