Control file Multiplexing

Static and Dynamic

MULTIPLEXING USING SPFILE

SQL> select name from v$controlfile;

NAME
------------------------------------------------------------------
/u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_.ctl
/u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_1.ctl

SQL> alter system set control_files=
'/u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_.ctl',
'/u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_1.ctl',
'/u01/app/oracle/oradata/TRAINING/control01.dbf' scope=spfile;

System altered.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.


SQL> !cp /u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_.ctl 
/u01/app/oracle/oradata/TRAINING/control01.dbf


SQL> startup

ORACLE instance started.

Total System Global Area 2432695144 bytes
Fixed Size                  8899432 bytes
Variable Size             536870912 bytes
Database Buffers         1879048192 bytes
Redo Buffers                7876608 bytes

Database mounted.

Database opened.

SQL> select name from v$controlfile;

NAME
--------------------------------------------------------------------------------
/u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_.ctl
/u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_1.ctl
/u01/app/oracle/oradata/TRAINING/control01.dbf


SQL> create pfile from spfile;

File created.

MULTIPLEXING USING PFILE

Multiplexing is the process of mintaining a copy of same control files on different disk drivers (and idealy on different controllers). To multiplex your control files, we copy the control file to multiple locations and change the CONTROL_FILES parameter in the text based initialization file init.ora to include all control files names.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.

SQL> exit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - 
Production Version 19.3.0.0.0

[oracle@training ~]$ cd $ORACLE_HOME/dbs


[oracle@training dbs]$ vi inittraining.ora


*.control_files='/u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_.ctl',
'/u01/app/oracle/oradata/TRAINING/controlfile/o1_mf_j9bdm6dk_1.ctl',
'/u01/app/oracle/oradata/TRAINING/control01.dbf'

[oracle@training dbs]$ cp /u01/app/oracle/oradata/TRAINING/control01.dbf 
/u01/app/oracle/oradata/TRAINING/control02.dbf

[oracle@training dbs]$ sqlplus / as sysdba



SQL> startup pfile=$ORACLE_HOME/dbs/inittraining1.ora

ORACLE instance started.

Total System Global Area 2432695144 bytes
Fixed Size                  8899432 bytes
Variable Size             536870912 bytes
Database Buffers         1879048192 bytes
Redo Buffers                7876608 bytes
Database mounted.
Database opened.

SQL> select name from v$controlfile;

NAME
--------------------------------------------------------------------------------
/u01/app/oracle/oradata/TRAINING1/controlfile/o1_mf_j9bdm6dk_.ctl
/u01/app/oracle/oradata/TRAINING1/controlfile/o1_mf_j9bdm6dk_1.ctl
/u01/app/oracle/oradata/TRAINING1/control01.dbf
/u01/app/oracle/oradata/TRAINING1/control02.dbf


SQL> create spfile from pfile;

File created.

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