Oracle Database Control file

Control files has the status of the physical structure of a database.  A control file should be backup whenever a change is made to the database.The controlfile contains the following sections:

• ARCHIVED LOG (reusable)
• BACKUP SET (reusable)
• BACKUP DATAFILE (reusable)
• BACKUP CORRUPTION (reusable)
• BACKUP PIECE (reusable)
• BACKUP REDOLOG (reusable)
• BACKUP SET (reusable)
• BACKUP SPFILE
• CKPT PROGRESS
• COPY CORRUPTION (reusable)
• DATABASE
• DATAFILE
• DATAFILE COPY (reusable)
• DATAFILE HISTORY
• DATABASE INCARNATION
• DELETED OBJECT (reusable)
• FILENAME
• FLASHBACK LOG
• INSTANCE SPACE RESERVATION
• LOG HISTORY (reusable)
• MTTR
• OFFLINE RANGE (reusable)
• RECOVERY DESTINATION
• REMOVABLE RECOVERY FILES
• RMAN STATUS
• RMAN CONFIGURATION
• REDO THREAD
• PROXY COPY 
• TABLESPACE
• TEMPORARY FILENAME
• THREAD INSTANCE NAME MAPPING

To view control file status
SQL> show parameter control_files

To backup control file before any operation:
SQL> alter database backup controlfile to 'c:\ora\control01.ctl'

Multiplexing of control files:
Can be done by giving the following line in pfile: control_files='E:\app\oradata\revolt\control01.ctl','E:\app\oradata\revolt\control02.ctl'

Recovery of database without controlfile and redolog
alter database backup controlfile to trace resetlogs