Oracle 11g rac在建库的时候使用了ASM存储，然而rac在建库时默认只在asm上面创建了一个控制文件，如果想多加几个控制文件，
就需要通过手工来添加了，很多人可能会忽略这个细节，但是我们还是希望多建几个control file来增加数据库的稳定性。
下面是具体步骤：


1、在操作前要保留一份控制文件和参数文件，以备搞不成恢复用。
注：只在一个数据库实例上进行修改。


SQL> create pfile='/home/oracle/pfile0531.ora' from spfile;
File created.
SQL> alter database backup controlfile to '/home/oracle/cntrl_20180531.ctl';
Database altered.


SQL> col name for a50
SQL> select * from gv$controlfile;
   INST_ID STATUS  NAME                                               IS_ BLOCK_SIZE FILE_SIZE_BLKS
---------- ------- -------------------------------------------------- --- ---------- --------------
         2         +DATA/crmdb/controlfile/current.282.873504505    NO       16384           1152
         1         +DATA/crmdb/controlfile/current.282.873504505    NO       16384           1152


2、修改spfile中的控制文件参数
SQL> alter system set control_files='+DATA/crmdb/controlfile/current.256.977420629','+DATA','+DATA' scope=spfile sid='*';
System altered.


3、关闭数据库实例
crmdb1:/home/oracle@db> srvctl stop database -d crmdb
 
4、创建control file 副本
crmdb1:/home/oracle@db>  rman target/
Recovery Manager: Release 11.2.0.4.0 - Production on 星期五 2月 6 15:50:12 2015
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
connected to target database (not started)
RMAN>  startup nomount
Oracle instance started
Total System Global Area   68412682240 bytes
Fixed Size                     2263488 bytes
Variable Size              31675385408 bytes
Database Buffers           36507222016 bytes
Redo Buffers                 227811328 bytes


RMAN> restore controlfile from '+DATA/crmdb/controlfile/current.256.977420629';
Starting restore at 06-2月 -15
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=4086 instance=crmdb device type=DISK
channel ORA_DISK_1: copied control file copy
output file name=+DATA/crmdb/controlfile/current.256.870194351
output file name=+DATA/crmdb/controlfile/current.426.870969063
output file name=+DATA/crmdb/controlfile/current.427.870969063
Finished restore at 06-2月 -15


RMAN> sql ' alter database mount';
sql statement:  alter database mount
released channel: ORA_DISK_1
RMAN> sql ' alter database open';
sql statement:  alter database open


5、登录数据库验证
SQL> select name from gv$controlfile;


NAME
--------------------------------------------------------------------------------
+DATA/crmdb/controlfile/current.256.977420629
+DATA/crmdb/controlfile/current.276.977568423
+DATA/crmdb/controlfile/current.277.977568423


6、修改spfile中的新添加的控制文件参数
SQL> alter system set control_files='+DATA/crmdb/controlfile/current.256.977420629','+DATA/crmdb/controlfile/current.276.977568423','+DATA/crmdb/controlfile/current.277.977568423' scope=spfile sid='*';
System altered.
SQL>  shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.


7、打开数据库最终验证
crmdb1:/home/oracle@db> srvctl start database -d crmdb
SQL>  select * from  gv$controlfile;
   INST_ID STATUS  NAME                                               IS_ BLOCK_SIZE FILE_SIZE_BLKS
---------- ------- -------------------------------------------------- --- ---------- --------------
         1         +DATA/crmdb/controlfile/current.256.977420629     NO       16384           1512
         1         +DATA/crmdb/controlfile/current.276.977568423     NO       16384           1512
         1         +DATA/crmdb/controlfile/current.277.977568423     NO       16384           1512
         2         +DATA/crmdb/controlfile/current.256.977420629     NO       16384           1512
         2         +DATA/crmdb/controlfile/current.276.977568423     NO       16384           1512
         2         +DATA/crmdb/controlfile/current.277.977568423     NO       16384           1512
6 rows selected.

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