POST is a group of PROM-based tests that run when the server is powered on or when it is reset. POST checks the basic integrity of the critical hardware components in the server (CMP, memory, and I/O subsystem).
You can also run POST as system-level hardware diagnostic tool. To do this, use the Oracle ILOM set command to set the parameter keyswitch_state to diag.
You can also set other Oracle ILOM properties to control various other aspects of POST operations. For example, you can specify the events that cause POST to run, the level of testing POST performs, and the amount of diagnostic information POST displays. These properties are listed and described in Oracle ILOM Properties that Affect POST Behavior.
If POST detects a faulty component, the component is disabled automatically. If the system is able to run without the disabled component, it will boot when POST completes its tests. For example, if POST detects a faulty processor core, the core will be disabled and, once POST completes its test sequence, the system will boot and run using the remaining cores.