I noticed an alert on two UCS B250M2 hosts in the vSphere Client. The alert Name was “Status of other host hardware objects”. This isn’t helpful. To get more information, you have to navigate to the Hardware Status tab of the host properties. Here I saw more information about the alert. It’s cryptically named “System Board 0 SEL_FULLNESS”.

This points to the System Event Log for the UCS blade itself. Luckily, this is easily cleared by using the UCS Manager to navigate to the management Logs tab of the Server properties under Equipment.

Once there, you can back up and clear the SEL. Within a few minutes, the vSphere sensors will update and the alert will be gone.
UPDATE: Once UCSM has been updated to 1.4.1, the “Management Logs” tab is named “SEL Logs”