vmnic link down for few seconds

Products

• VMware vSphere ESXi

Issue/Introduction

• vmnic using nmlx5-core link down for few seconds.
• Log indicates that its driver detected link down/up.

cpu0:2098185)netschedHClk: NetSchedHClkNotify:4662: vmnic5: link down notification
cpu0:2098185)<NMLX_INF> nmlx5_core: vmnic5: nmlx5_en_UplinkLinkStateSetOS - (nmlx5_core_en_uplink.c:5065) Changing link status from UP Full Duplex 25000 to DOWN Half Duplex 0
cpu0:2098185)<NMLX_INF> nmlx5_core: vmnic5: nmlx5_en_UpdatePhyData - (nmlx5_core_en_main.c:1038) called
cpu0:2098185)netschedHClk: NetSchedHClkNotify:4654: vmnic5: link up notification
cpu0:2098185)<NMLX_INF> nmlx5_core: vmnic5: nmlx5_en_UplinkLinkStateSetOS - (nmlx5_core_en_uplink.c:5065) Changing link status from DOWN Half Duplex 0 to UP Full Duplex 25000
cpu0:2098185)<NMLX_INF> nmlx5_core: vmnic5: nmlx5_en_UpdatePhyData - (nmlx5_core_en_main.c:1038) called

• Other cards/drivers might have similar messages
  
  

Environment

VMware ESXi

Cause

The log means nmlx5 driver simply detected link down/up. Drivers usually detect link state based on hardware register value and usually it is not a software issue.

Resolution

Recommendation is to engage hardware/network vendor for further investigation.

Additional Information

VMware by Broadcom Compatibility Guide
vmnic のリンクが数秒間ダウンする