Network Performance Test reporting Health Status as Failed

Products

• VMware vSAN

Issue/Introduction

The Network performance test can be used to assess if there are any connectivity issues in the network used by vSAN. In addition, the result can be used as a reference to check if the network speed among the hosts meets the hardware specification and is sufficient to support the workloads hosted on vSAN. 

Symptom: 

• vSAN Proactive Network Performance Test in Host and Cluster View > Monitor > vSAN > Proactive Test > Network Performance Test reporting as Failed.

• VM creation test completes successfully for all hosts.
• No Cluster Partition reported in the vSAN cluster..
  
  
• In the above screenshot, the Network Performance Test on the vSAN VMkernel is failing when connecting to Host-ESXi03 from Host-ESXi02 and Host-ESXi04. This suggests a potential issue on Host-ESXi03 when other hosts attempt to test bandwidth with it.
  
  
  
• Manual iPerf test between the hosts (Using iPerf for Testing vSAN Network Performance) from CLI will fail with the error highlighted below:

To start iPerf in Server Mode on the Host-ESXi03:

ESXI03: /usr/lib/vmware/vsan/bin] /usr/lib/vmware/vsan/bin/iperf3 -s -B VSAN_VMKernel_IP -i 1    

Server listening on 5201 (test #1)

 

To Start iPerf in Client Mode on one Host-ESXi02:

• ESXi02: /usr/lib/vmware/vsan/bin/iperf3 -c VSAN_VMKernel_IP_of_HOST-ESXi03 -fM 

iperf3: error - unable to connect to server - server may have stopped running or use a different port, firewall issue, etc .: Connection timed out 

 

• • •  

Environment

VMware vSAN 7.x
VMware vSAN 8.x

Cause

This issue could be due to:

• Connectivity issue between the host using vSAN network.
• If any issues with the iPerf module on ESXi host.

Resolution

• Ensure the firewalls are configured to allow traffic on port 5201 between the vSAN network of ESXi hosts.
• Put the host in maintenance mode with ensure accessibility option and power cycle the host which will reload the iPerf modules

Additional Information

To know more about network performance test, Refer to this article:  vSAN -- Health Service -- Proactive Tests -- Network Performance Test

How to use iPerf for testing vSAN Network Performance:  Using iPerf for Testing vSAN Network Performance