Alarm : High pNic error rate detected due to Receive CRC errors in vSAN 8.x

Products

• VMware vSphere ESXi

Issue/Introduction

• vSAN health alarm triggers: High pNic error rate detected. Check the host's vSAN performance view for details.
  
  
  • This alarm specifically monitors physical network card (vmnic) counters for CRC errors, which can impact vSAN data integrity and cluster performance.
    
    
• vCenter Summary page may report error rates exceeding 100% on the affected ESXi host.
  
  
• CLI output from  esxcli network nic stats get -n vmnic#  shows incrementing  Receive CRC errors
  
  
  • Outputs may also increment for   Receive packets dropped   and  Receive length errors.     
    
    
  • Example Output:
    
    NIC statistics for vmnic#:
      Packets received: 21416979733
      Packets sent: 662987
      Bytes received: 15230944710898
      Bytes sent: 152483213
      Receive packets dropped: 0
      Transmit packets dropped: 0
      Multicast packets received: 126740264
      Broadcast packets received: 2797349323
      Multicast packets sent: 662965
      Broadcast packets sent: 22
      Total receive errors: 5951636
      Receive length errors: 0
      Receive over errors: 0
      Receive CRC errors: 5951636
      Receive frame errors: 0
      Receive FIFO errors: 0
      Receive missed errors: 0
      Total transmit errors: 0
      Transmit aborted errors: 0
      Transmit carrier errors: 0
      Transmit FIFO errors: 0
      Transmit heartbeat errors: 0
      Transmit window errors: 0

   

Environment

 VMware vSAN 8.x
 VMware ESXi 8.x

Cause

Cyclic Redundancy Check (CRC) errors indicate that data packets were altered or corrupted during transit across the physical medium (cables, SFPs, or switch ports). Because the NIC hardware discards these corrupted frames before they reach the ESXi driver, this is strictly a Physical Layer (Layer 1) issue.

Common specific causes include:

• Faulty, loose, or damaged Direct Attach Copper (DAC) cables, or poor fiber/cable seating
  
  
• Defective SFP/transceiver modules or degraded network adapter ports.
  
  
• Misconfigured or failing physical switch ports.
     

Resolution

1. Run the following command on the affected host:    esxcli network nic stats get -n vmnic#
   
   
2. Monitor the Receive CRC errors counter over a 5-minute interval. If the counter increments, the issue is active and occurring on that physical path.
   
   
3. Provide the collected esxcli output to your network team, as this confirms the corruption is occurring external to the ESXi host.
   
   
4. Perform a structured hardware isolation:
   
   
   • Inspect and replace the network cable.
     
     
   • Replace the SFP+ transceiver.
     
     
   • Move the connection to a known, good upstream physical switch port to rule out switch-side defects.
     
     
5.  Confirm that the Receive CRC errors counter stops incrementing following the replacement or port move.
   
   

To speak with a Broadcom customer representative or a Support Engineer, if needed, see  Contact Support.

Additional Information

For additional details on the "High pNic error rate detected" alarm, see vSAN -- Alarm about high pNIC error rate being detected. 

It is recommended to Subscribe to this article. Reference: (KB 275360) Subscribe to a Broadcom knowledge article by article or product to be updated on any changes to this alarm's monitoring logic.