Had a tricky issue with the vSAN Health check plugin recently, where a warning was reporting issues with some hosts not contributing vSAN performance stats.

Thanks to vmscribble‘s post detailing the requirement for the vSphere Web Access ruleset being enabled, it turns out that the issue was due to my ESXi hosts Host Profile incorrectly disabling the vSphere Web Access ruleset in the security profile when the host was being remediated against it.

Enabling vSphere Web Access ruleset in the security profile as per the above screenshot for each host fixed the issue, followed by ensuring the Host Profile also had vSphere Web Access ruleset enabled as shown below:

So make sure that your Host Profiles are created after adding your hosts to vSAN, to ensure all rulesets etc are current!