Control file contains crucial database information and loss of this file will lead to loss of important data about database. So it is recommended to have multiplexed copies of files in different locations.
If control file is lost in 9i, database may go for force shutdown, where as database will continue to run, if it is 10g version and above.
Check if the database is running with spfile
SQL> show parameter spfile
If yes, then check the control files
SQL> show parameter control_files
Now add the new controlfile to below command along with old controlfiles from above command. We will add control03.ctl
SQL> alter system set control_files='/u02/prod/control01.ctl','/u02/prod/control02.ctl','/u02/prod/control03.ctl' scope=spfile;
We need to bounce the database and copy control02.ctl as control03.ctl
SQL> shutdown immediate SQL> ! cp /u02/prod/control01.ctl /u02/prod/control04.ctl
Start the database