Just a question. We had a controller that a PSU was turned off mistakenly and wasn't noticed until someone physically noticed it some days after the fact. Why doesn't SysMan show that the controller is degraded from the 'Home' screen so at least you will then delve in and investigate the issue. The site I am at has little to no monitoring.
Dashboard health monitor/notifications is not very comprehensive today in System Manager. There are certain technical difficulties in getting all the notifications and reminders from Data ONTAP. We are working towards it to make it better (by including alerts and notifications from various subsystems in ONTAP )