Here is something I ran into the other day at work that might help anyone else getting this issue. VMWare also told me that this tends to happen from time to time on an ESX 3.5 infrastructure. Apparently the issue has been sorted out in vSphere. It doesn’t have any negative effect on production though, apart from the fact that you can’t see your host health statuses correctly.
Also I wouldn’t recommend only relying on these health statistics. Install Dell’s OMSA for extra health monitoring and statistics if you are running Dell servers for example.
Problem:
The Pegasus hardware health service needs restarting or a specific ESX host in the Virtual Center cluster is not showing it’s hardware health indicators in VC correctly. (Could be showing as “Unknown”).
Solution:
Log into the console of the ESX Host in question using PuTTy (SSH).
Run the following command from the ESX server console as root to restart the Pegasus service.
service pegasus restart
I did speak to VMWare support about this and they have said that this does not have any effect on live VMs. I have tested this in a live environment twice now and it did not affect any Virtual Machines.
In both cases I needed to wait 5 to 10 minutes for the ESX host health to update in Virtual Center.
Note that restarting the pegasus health monitoring service does not affect any running VMs on your host.