Storage Paths are flapping between offline and online for a single HBA on a host

Products

• VMware vSphere ESXi
• VMware vSphere ESX 5.x
• VMware vSphere ESX 6.x
• VMware vSphere ESX 7.x
• VMware vSphere ESX 8.x
• VMware vSphere ESXi 5.0
• VMware vSphere ESXi 5.5
• VMware vSphere ESXi 8.0

Issue/Introduction

An Administrator observes frequent and repeated FC storage path down and then up events on an ESXi host. When reviewing the pathing information for the LUN, only a single path remains instead of the expected number (usually 4):

naa.60000970000##################### : EMC Fibre Channel Disk (naa.60000970000#####################)
   vmhba2:C0:T5192:L1 LUN:1 state:active fc Adapter: WWNN: 20:00:00:25:##:##:##:## WWPN: 20:00:00:25:##:##:##:##  Target: WWNN: 50:00:09:73:##:##:##:## WWPN: 50:00:09:73:##:##:##:##

naa.60000970000##################### : EMC Fibre Channel Disk (naa.60000970000#####################)
   vmhba2:C0:T5192:L2 LUN:2 state:active fc Adapter: WWNN: 20:00:00:25:##:##:##:## WWPN: 20:00:00:25:##:##:##:##  Target: WWNN: 50:00:09:73:##:##:##:## WWPN: 50:00:09:73:##:##:##:##

 

Cause

When reviewing /var/log/vmkernel.log, a behavior is observed where an HBA is being forced off the fabric with a fabric logout request (LOGO) exactly every 40 seconds from the same Fabric IDs indefinitely, which is what is causing the flapping behavior:

2025-04-09T15:10:31.044Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421961
2025-04-09T15:10:31.044Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421760
2025-04-09T15:11:11.053Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421961
2025-04-09T15:11:11.053Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421760
2025-04-09T15:11:51.060Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421961
2025-04-09T15:11:51.061Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421760
2025-04-09T15:12:31.068Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421961
2025-04-09T15:12:31.069Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421760
2025-04-09T15:13:11.076Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421961
2025-04-09T15:13:11.077Z cpu38:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421760
2025-04-09T15:13:51.084Z cpu29:2097816)nfnic: <1>: INFO: fdls_process_logo_req: 3616: Process LOGO request from fcid: 0x421961 



Resolution

Contact the fabric switch vendor for assistance. This issue occurs when there is a zoning problem on the fabric switches, specifically with inactive zones still running in memory on the switch itself.