I’m unable to view hardware health status data while a host is in maintenance mode in my vSphere 4.0 Update 1 environment.
A failed memory module was replaced on a host but I’m skeptical about taking it out of maintenance mode until I am sure it is healthy. There is enough load on this cluster such that removing the host from maintenance mode will result in DRS moving VM workloads onto it within five minutes. For obvious reasons, I don’t want VMs running on an unhealthy host.
So… I need to disable DRS at the cluster level, take the host out of maintenance mode, verify the hardware health on the Hardware Status tab, then re-enable DRS. It’s a round about process, particularly if it’s a production environment which requires a Change Request (CR) with associated approvals and lead time to toggle the DRS configuration.
Taking a look at KB 1011284, VMware acknowledges the steps above and considers the following a resolution to the problem:
By design, the host monitoring agents (IPMI) are not supported while the ESX host is in maintenance mode. You must exit maintenance mode to view the information on the Hardware Status tab. To take the ESX host out of maintenance mode:
1.Right click ESX host within vSphere Client.
2.Click on Exit Maintenance Mode.
Fortunately, this design specification has been improved by VMware in vSphere 4.1 where I have the ability to view hardware health while a host is in maintenance mode.