1.—关闭数据库，各个节点都要关闭：

[oracle@rac1 ~]$ srvctl stop database -d racdb -o immediate

2.—启动任一节点到nomount状态：

[oracle@rac1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Thu Dec 29 14:32:06 2016

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to an idle instance.

SYS@RACDB1> startup nomount

ORACLE instance started.

Total System Global Area  730714112 bytes

Fixed Size                  2256832 bytes

Variable Size             322961472 bytes

Database Buffers          402653184 bytes

Redo Buffers                2842624 bytes

SYS@RACDB1> create pfile='/home/oracle/initracdb.ora' from spfile;

File created.

SYS@RACDB1> exit

Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, Real Application Clusters, OLAP, Data Mining

and Real Application Testing options

3.—使用rman备份控制文件：

[oracle@rac1 ~]$ rman target/

Recovery Manager: Release 11.2.0.4.0 - Production on Thu Dec 29 14:33:59 2016

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: RACDB (not mounted)

4.—因为OMF机制，此处备份出来的文件可以指定准确路径，也可以如下指定：

RMAN> restore controlfile to '+DATA' from '+DATA/racdb/controlfile/current.260.931717363';

Starting restore at 29-DEC-16

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=35 instance=RACDB1 device type=DISK

channel ORA_DISK_1: copied control file copy

Finished restore at 29-DEC-16

RMAN> restore controlfile to '+DATA' from '+DATA/racdb/controlfile/current.260.931717363';

Starting restore at 29-DEC-16

using channel ORA_DISK_1

channel ORA_DISK_1: copied control file copy

Finished restore at 29-DEC-16

RMAN> exit

Recovery Manager complete.

5.—在grid用户下登录asmcmd查看备份的控制文件：

[oracle@rac1 ~]$ su - grid

Password:

[grid@rac1 ~]$ asmcmd

ASMCMD> cd data/racdb/controlfile

ASMCMD> pwd

+data/racdb/controlfile

ASMCMD> ls

Current.260.931717363

current.286.931876547

current.287.931876517

ASMCMD> exit

6.—修改数据库的参数文件，把备份出来的控制文件添加到参数文件中：

[oracle@rac1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Thu Dec 29 14:38:45 2016

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

Data Mining and Real Application Testing options

SYS@RACDB1> select inst_id,host_name,status from gv$instance;

   INST_ID HOST_NAME                                                        STATUS

---------- ---------------------------------------------------------------- ------------

         1 rac1                                                             STARTED

SYS@RACDB1> alter system set control_files=

  2  '+data/racdb/controlfile/Current.260.931717363',

  3  '+data/racdb/controlfile/current.286.931876547',

  4  '+data/racdb/controlfile/current.287.931876517'

  5  scope=spfile;

System altered.

7.—修改完参数文件后，关闭数据库：

SYS@RACDB1> shutdown abort;

ORACLE instance shut down.

SYS@RACDB1> exit

Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,

Data Mining and Real Application Testing options

8.—同时打开所有节点，查看控制文件的设置情况：

[oracle@rac1 ~]$ srvctl start database -d racdb -o open

SYS@RACDB1> select inst_id,name from gv$controlfile;

 INST_ID NAME

---------- --------------------------------------------------

         1 +DATA/racdb/controlfile/current.260.931717363

         1 +DATA/racdb/controlfile/current.286.931876547

         1 +DATA/racdb/controlfile/current.287.931876517

         2 +DATA/racdb/controlfile/current.260.931717363

         2 +DATA/racdb/controlfile/current.286.931876547

         2 +DATA/racdb/controlfile/current.287.931876517

6 rows selected.

至此控制文件的多路复用得以实现！

**总结：
控制文件多路复用的关键点是：
①rman复制控制文件之前要同时关闭所有节点；
②参数文件要在记得修改；
③同时打开所有节点。**