This article explains the Network health - Hosts with connectivity issues check in the vSAN Health Service and provides details on why it might report an error.

VMware vSAN 6.0.x
VMware vSAN 8.0.x
VMware vSAN 7.0.x

Q: What does the Network Health - Hosts with connectivity issues check do?

This check refers to situations where the vCenter Server lists the ESXi host as connected, but all of vSAN API calls from the vCenter Server to the ESXi host affected are failing. This situation should be extremely rare, but in case it happens, it leads to similar issues as the Host disconnected from vCenter situation.

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

If this health check highlights that an ESXi host has connectivity issues, vCenter Server does not know its state. The host may be up and may be actively participating in the vSAN cluster, serving data, and being healthy and performing its storage functions as part of the vSAN cluster.

However, it could also mean that either the vSAN management daemon on the ESXi host may be down and unavailable. The vCenter Server, and hence the vSAN Health check, cannot fully assess the situation as long the host is disconnected.

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

You could first check the management network between vCenter and host and make sure it's fine. If the problem is still there, you could connect to the host via SSH and check the vSAN management daemon status with the command "/etc/init.d/vsanmgmtd status" and restart it by "/etc/init.d/vsanmgmtd restart".