vSAN Health Service - Network - vSAN Max Client Network connectivity check

Products

• VMware vSAN

Issue/Introduction

This article introduces the new vSAN Skyline Health check 'vSAN Max Client Network connectivity check' in vSAN 9.0 and provides details on why it might report an error and how to fix the error state.

Environment

VMware vSAN 9.0

Resolution

Q: What does the 'vSAN Max Client Network connectivity check' check do? 

It performs a connectivity check for vSAN Max Client Network by checking the heartbeats from each host to all other hosts in the server cluster. If this check fails, there is a basic issue with network connectivity for vSAN Max Client Network.

Q: What does it mean when it is in an error state?

The remote client cluster might run with degraded performance. It may impact the objects accessibility from the remote client cluster when all vmknics for vSAN Max client network can't connect to each other. 

The health check will be shown as yellow (warning) when the vSAN Max Client network connectivity is unstable among ESXi hosts and if the vSAN Max Client network connectivity is down among ESXi hosts, which could indicate either virtual network configuration issues (such as problems with VMkernel adapters and Virtual Switches), or physical network issues (such as problems with cables, physical NICs and physical switches), a red health is displayed.

Q: How does one troubleshoot and fix the error state?

Check for packet loss over the vSAN Max Client network by running the vmkping command from source ESXi host to the destination host's IP address of the vSAN Max Client network. 'vSAN Max Client VMkernel NIC' is the VMkernel adapter which is enabled vSAN Max Client. 'Destination IP' is the IP address of VMkernel adapter which is enabled the vSAN Max Client from the target host.

Command: vmkping -I <vSAN Max Client VMkernel NIC> <vSAN host IP>

Refer to Troubleshooting the vSAN Network for more details.

If there's no obvious networking issue, dump the missing heartbeat count from the source host with the below command and contact Broadcom for support.

Command: /bin/python -c "import pyCMMDS;output=pyCMMDS.GetExtVmkNicDetails(<vSAN Cluster UUID>);print(output)"