Control Files:
The control files of a database store the status of the physical structure of the database.
Controlfile Contains the following type of information:
1. Archive log history
2. Tablespace and datafile records (filenames, datafile checkpoints, read/write status, offline or not)
3. Current redo log file sequence number
4. Database's creation date
5. database name
6. current archive log mode
7. Backup information
8. Database block corruption information
9. Database ID, which is unique to each DB
Multiplexing Control file using SPFILE:
SQL>ALTER SYSTEM SET control_files=
C:\oracle\product\10.2.0\oradata\dba01\CONTROL01.CTL',
'C:\oracle\product\10.2.0\oradata\dba01\CONTROL02.CTL',
'C:\oracle\product\10.2.0\oradata\dba01\CONTROL03.CTL',
'C:\oracle\product\10.2.0\oradata\dba01\CONTROL04.CTL'
SCOPE=spfile;
SQL> shutdown;
C:\>copy C:\oracle\product\10.2.0\oradata\dba01\CONTROL01.CTL C:\oracle\product\10.2.0\oradata\dba01\CONTROL04.CTL
startup;
Multiplexing Control file using SPFILE:
1. shutdown
2. C:\>copy C:\oracle\product\10.2.0\oradata\dba01\CONTROL01.CTL C:\oracle\product\10.2.0\oradata\dba01\CONTROL04.CTL
3. Add new file in the PFILE
control_files='C:\oracle\product\10.2.0\oradata\dba01\control01.ctl','C:\oracle\product\10.2.0\oradata\dba01\control02.ctl','C:\oracle\product\10.2.0\oradata\dba01\control03.ctl','C:\oracle\product\10.2.0\oradata\dba01\control04.ctl'
4. startup pfile=’C:\oracle\product\10.2.0\admin\dba01\pfile\init.ora';