Follow the steps below to multiplex the Control File.
RAC ASM Environment
STEP 1
Connect to any one of the RAC nodes and check the current control file status
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Sun Apr 25 07:55:12 2021
Version 19.8.0.0.0
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.8.0.0.0
SQL> select name from v$controlfile;
NAME
--------------------------------------------------------------------------------
+DATA/ORADB/CONTROLFILE/current.256.1155470367
STEP 2
Modify the control_files parameter by adding the new disk group
SQL> alter system set control_files='+DATA/ORADB/CONTROLFILE/current.256.1155470367','+FRA' scope=spfile;
System altered.
SQL> exit
STEP 3
Shutdown the RAC database and start it in nomount mode
$ srvctl stop database -d ORADB
$ srvctl start database -d ORADB -o nomount
STEP 4
Check the database to confirm addition of new diskgroup to the control_files parameter
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Sun Apr 25 07:59:11 2021
Version 19.8.0.0.0
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.8.0.0.0
SQL> show parameter control_files
NAME TYPE VALUE
--------------- ------------- ------------------------------
control_files string +DATA/ORADB/CONTROLFILE/current.256.1155470367, +FRA
SQL> exit
STEP 5
Connect to RMAN and use the restore command to create a copy of the control file
$ rman target /
Recovery Manager: Release 19.0.0.0.0 - Production on Sun Apr 25 08:04:19 2021
Version 19.8.0.0.0
Copyright (c) 1982, 2019, Oracle and/or its affiliates. All rights reserved.
connected to target database: ORADB(not mounted)
RMAN> restore controlfile from '+DATA/ORADB/CONTROLFILE/current.256.1155470367';
Starting restore at 25-APR-21
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=53 instance=ORADB1 device type=DISK
channel ORA_DISK_1: copied control file copy
output file name=+DATA/ORADB/CONTROLFILE/current.256.1155470367
output file name=+FRA/ORADB/CONTROLFILE/current.263.1157817489
Finished restore at 25-APR-21
RMAN> exit
Take notice of the newly generated control file ‘+FRA/ORADB/CONTROLFILE/current.263.1157817489’
STEP 6
Connect to sqlplus and modify the contol_files parameter
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Sun Apr 25 08:06:15 2021
Version 19.8.0.0.0
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.8.0.0.0
SQL> alter system set control_files='+DATA/ORADB/CONTROLFILE/current.256.1155470367','+FRA/ORADB/CONTROLFILE/current.263.1157817489' scope=spfile;
System altered.
SQL> exitSTEP 7
Shutdown the database and start up normal
$ srvctl stop database -d ORADB
$ srvctl start database -d ORADB
STEP 8
Connect to sqlplus and confirm muliplex of the control file
$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Sun Apr 25 08:03:15 2021
Version 19.8.0.0.0
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.8.0.0.0
SQL> show parameter control_files
NAME TYPE VALUE
---------------- ----------- ------------------------------------------
control_files string +DATA/ORADB/CONTROLFILE/current.256.1155470367,
+FRA/ORADB/CONTROLFILE/current.263.1157817489
SQL> select name from v$controlfile;
NAME
------------------------------------------------------------------------
+DATA/ORADB/CONTROLFILE/current.256.1155470367
+FRA/ORADB/CONTROLFILE/current.263.1157817489
Non-ASM Environment
STEP 1
Check the current control file
[oracle@srv1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Sun Apr 25 09:55:21 2021
Version 19.8.0.0.0
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.8.0.0.0
SQL> select name from v$controlfile;
NAME
--------------------------------------------------------------------------------
/u01/app/oracle/oradata/ORADB/control01.ctl
/u01/app/oracle/fra/ORADB/control02.ctl
SQL> exit
STEP 2
Modify the control_files parameter by adding a new disk location. We will use this location ‘/u02/oracle/ORADB’
$ mkdir -p /u02/oracle/ORADB
$ chown -R oracle:oinstall /u02
$ chmod -R 775 /u02
SQL> alter system set control_files='/u01/app/oracle/oradata/ORADB/control01.ctl','/u01/app/oracle/fra/ORADB/control02.ctl','/u02/oracle/ORADB/control03.ctl' scope=spfile;
System altered.STEP 3
Shutdown the database and copy the control file to the newly created location
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 19.8.0.0.0
[oracle@srv1 ~]$
[oracle@srv1 ~]$ cp /u01/app/oracle/oradata/ORADB/control01.ctl /u02/oracle/ORADB/control03.ctl
STEP 4
Startup the database and check the control_files parameter
[oracle@srv1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 19.0.0.0.0 - Production on Sun Apr 25 10:06:08 2021
Version 19.8.0.0.0
Copyright (c) 1982, 2020, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 1073738888 bytes
Fixed Size 9143432 bytes
Variable Size 553648128 bytes
Database Buffers 503316480 bytes
Redo Buffers 7630848 bytes
Database mounted.
Database opened.
SQL>
SQL>
SQL> select name from v$controlfile;
NAME
--------------------------------------------------------------------------------
/u01/app/oracle/oradata/ORADB/control01.ctl
/u01/app/oracle/fra/ORADB/control02.ctl
/u02/oracle/ORADB/control03.ctl
SQL>