Recover Missing Control File From Multiplexed Copy

Control file is very important file for Oracle database, without controlfile your database will able to mount your database (your database will able to be started no mount). You may refer to Oracle Database Startup Process and Oracle Database Shutdown Process. Oracle Support always recommend Oracle user to multiplex the control file in different mount point, so that failure of one disk partition will not causing total lost of all control files.

To recover missing control file from the multiplex is as easy as copy from the multiplexed copy of control file.

In my example I have 3 multiplexed controlfile as you can see I put all in same mount point, well this is just a test virtual server to test the concept :)

/datafiles/edba01/edba01/control01.ctl
/datafiles/edba01/edba01/control02.ctl
/datafiles/edba01/edba01/control03.ctl

I delete 1 of the controlfile to stimulate losing one of my control files

rm /datafiles/edba01/edba01/control01.ctl

without that controlfile database will not be able to be mounted during the startup

startup

Read the alert log file for detail information of the error.

tail -10 /u01/app/oracle/diag/rdbms/edba01/trace/alert_edba01.log

I still have 2 more copies of my control file, I recreate the missing one with the one that still exits.

cp /datafiles/edba01/edba01/control02.ctl /datafiles/edba01/edba01/control01.ctl

After recover the control file, I am try to mount and open the database.

ALTER DATABASE MOUNT;

ALTER DATABASE OPEN;

I am checking the status of the database.

SELECT open_mode FROM v$database;

and it is open READ WRITE.