Newly assigned LUNs are not visible on the ESXi host

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• The ESXi host is failing to discover newly provisioned Fibre Channel LUNs following a storage adapter rescan:
  

Environment

VMware vSphere ESXi 8.x

Cause

• The below vmkernel.log entry WARNING , indicate that thenfnic driver (used for FCoE/FC on Cisco UCS) has reached the maximum allowable storage paths in ESXi and cannot add more. 

  ####-##-##T##:##:##.###Z Wa(###) vmkwarning: cpu38:#######)WARNING: nfnic: <1>: fnic_handle_report_lun: 1533: lun add failure! in_remove: 0 ioAllowed: 1

  ####-##-##T##:##:##.###Z Wa(###) vmkwarning: cpu38:#######)WARNING: nfnic: <1>: fnic_tport_event_handler: 2136: lunmap update failed,retry ..

  ####-##-##T##:##:##.###Z In(###) vmkernel: cpu38:#######)nfnic: <1>: INFO: fnic_handle_report_lun: 1425: Report luns response for target_fcid : 0x213e0 target_id:10 num_luns 1

  ####-##-##T##:##:##.###Z In(###) vmkernel: cpu38:#######)nfnic: <1>: INFO: fnic_handle_report_lun: 1460: Primary LUN fcid: 0x213e0 target_id:10 primary_lun_num: 1

  ####-##-##T##:##:##.###Z Wa(###) vmkwarning: cpu38:#######)WARNING: nfnic: <1>: fnic_handle_report_lun: 1516: vmk_ScsiScanAndClaimPaths returned VMK_MAX_PATHS_CLAIMED

• As seen below, the ESXi host has reached the maximum ESXi configuration limit of 4,096 total SCSI paths. As this upper threshold has been met, the storage stack is unable to register additional paths or discover new devices during a rescan. 

  

   

Resolution

 As the maximum limit of 4,096 total SCSI paths is reached, reconfigure storage to reduce the total number of paths below 4096. If the path count isn't reduced, any future storage allocations will fail to be discovered.

Additional Information

vSphere 8.0 Configuration Limits