vSAN disk in unmounted and ineligible state

Products

• VMware vSAN

Issue/Introduction

Symptom: 

• vSAN disk naa.################ is in unmounted state on a vSAN node.

Validation:

• SSH to the vSAN node with the unmounted disk and run below command -
  
  [root@esxi1:~] esxcli vsan storage list | grep -i cmmds
   In CMMDS: true
   In CMMDS: true
   In CMMDS: true
   In CMMDS: false
  
  

Environment

VMware vSphere vSAN 7.x

VMware vSphere vSAN 8.x

Cause

• Faulty physical disk detected by vSAN. The disk state being faulty can be validated across multiple host logs -
  
  
  • SSH to the vSAN node and navigate to path "/var/run/log/vobd.log", to see below events -
     

    2025-03-03T00:30:07.975Z: [scsiCorrelator] 17381645978626us: [vob.scsi.scsipath.por] Power-on Reset occurred on naa.################
2025-03-03T00:31:22.527Z: [scsiCorrelator] 17381720530080us: [vob.scsi.device.too.many.io.error] Too many errors observed for device naa.################ errPercentage 74

  • In the "/var/run/log/vmkwarning.log", you will see entries similar to -
    
    2025-03-12T05:08:24.209Z cpu67:2101847 opID=3dbce423)WARNING: ScsiDeviceIO: 12155: READ CAPACITY on device "naa.################" from Plugin "HPP" failed. I/O error
2025-03-12T05:08:33.531Z cpu9:2104069)WARNING: ScsiDeviceIO: 12155: READ CAPACITY on device "naa.################" from Plugin "HPP" failed. I/O error

  • In the "/var/run/log/vmkernel.log", you will see entries similar to -
    
    2025-03-12T06:19:59.910Z cpu5:2101934 opID=de30a3c2)WARNING: ScsiDeviceIO: 12155: READ CAPACITY on device "naa.################" from Plugin "HPP" failed. I/O error
2025-03-12T06:19:59.910Z cpu2:34236323)ScsiDevice: 612: Could not flush cache of local device naa.################. Failure

Resolution

• Reboot the host after placing it into maintenance mode. 
  
  
• If the issue is seen even after rebooting the host, again open hardware interface and validate the state of the disks again.
  
  
• Reach out to the hardware vendor to investigate the state of the disk.

Additional Information

For more details refer Dying Disk Handling (DDH) in vSAN