While testing the my Oracle 11g environment, I found the enterprise manger does not auto start after the host reboot.
When I use emctl status dbconsole, it reply the “OC4J Configuration issue”. The emctl can not find the configuration file.
The configuration file does indeed exist but however it is the different name that emctl is looking for.
In the standalone environment, the emctl is looking for the same name as the ORACLE_SID.
In the RAC enviroment, it is looking for the name defined in the ORACLE_UNQNAME. After I reset the ORACLE_UNQNAME , I can now start the emctl successfully.