Recently i have come across an issue in lab where hosts from Vsan cluster is showing warning on host summary as shown in below screenshot:

Below are the checks performed:

1. Check cluster health – Found all green

2. Check host vSan status : All hosts in cluster are part of vsan cluster. Command used: esxcli vsan cluster get

3. Pro active tests passed

4. Does all hosts have same sub cluster UUID? – yes

Though this warning on hosts did not cause any problem to existing vm’s , was not able to disable or enable HA, adding new hosts to cluster caused network partition with new hosts having different sub cluster UUID. Hmm, that was an interesting issue and what is the issue ? How is the fix? Let’s get more deeper here