Every database has a control file, which contains entries that describe the structure of the database (such as its name, the timestamp of its creation, and the names and locations of its data and redo files). CONTROL_FILES specifies one or more names of control files, separated by commas.
In an Oracle Parallel Server environment, you must set this parameter for every instance.
Oracle Corporation recommends that you multiplex multiple control files on different devices or mirror the file at the operating system level.
