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Every Oracle database has a control file. A control file is a small binary file that records the physical structure of the database and includes:
The database name
Names and locations of associated datafiles and online redo log files
The timestamp of the database creation
The current log sequence number
Checkpoint information
Creating Initial Control Files
The initial control files of an Oracle database are created when you issue the CREATE DATABASE statement. The names of the control files are specified by the CONTROL_FILES parameter in the initialization parameter file used during database creation. The filenames specified in CONTROL_FILES should be fully specified and are operating system specific. The following is an example of a CONTROL_FILES initialization parameter:
CONTROL_FILES = (/u01/oracle/prod/control01.ctl,
/u02/oracle/prod/control02.ctl,
/u03/oracle/prod/control03.ctl)
To Multiplex or Move Additional Copies of the Current Control Files
You can create an an additional control file copy by copying an existing control file to a new location and adding the file's name to the list of control files. Similarly, you rename an existing control file by copying the file to its new name or location, and changing the file's name in the control file list. In both cases, to guarantee that control files do not change during the procedure, shut down the instance before copying the control file.
the step of creating multiplex in control files:-
1-Shut down the database.
2-Copy an existing control file to a different location, using operating system commands.
-Edit the CONTROL_FILES parameter in the database's initialization parameter file to add the new control file's name, or to change the existing control filename.
4-Restart the database
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