Multiplexing Oracle Control File

Posted by Asher
October 18, 2009

1 Multiplexing the control file when using SPFILE

Firstly, Obtain the information of your control file

SQL> select * from v$controlfile;

STATUS NAME IS_ BLOCK_SIZE FILE_SIZE_BLKS
/u01/oradata/helen/control01.ctl NO 16384 430
/u01/oradata/helen/control02.ctl NO 16384 430

also you can issue this command show parameter control_files to get the information of your control file.

Secondly, Make sure that your server is using the SPFILE

SQL> show parameter spfile; Aafter this command is executed,we should get some value like this

NAME TYPE VALUE
spfile string /u01/app/oracle/dbs/spfilehelen.ora

if there is no result returned (a truly result for the VALUE column in the above table),it means that your server is now using a PFILE. :lol:  How to Multiplexing Control File when using PFILE ? We will describe it soon . Now,we will multiplex the Control File:

① Alter the SPFILE

SQL> alter system set control_files= ‘/u01/oradata/helen/control01.ctl’,'/u01/oradata/helen/control02.ctl’,'/u01/oradata/control03.ctl’ scope=spfile;

SQL> alter system set control_files=’/u01/oradata/helen/control01.ctl’,

‘/u01/oradata/helen/control02.ctl’, ’/u01/oradata/control03.ctl’ scope=spfile;

System altered.

②  Shutdown the database

SQL> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

③  Create the additional Control File

[oracle@Linux10g ~]$ cp /u01/oradata/helen/control01.ctl /u01/oradata/control03.ctl

④  Startup the database

SQL> startup;

ORACLE instance started.

Total System Global Area  343932928 bytes

Fixed Size                  1219328 bytes

Variable Size              79693056 bytes

Database Buffers          260046848 bytes

Redo Buffers                2973696 bytes

Database mounted.

Database opened.

⑤ Identifying our Control File again

SQL> select * from v$controlfile;

STATUS NAME IS_ BLOCK_SIZE FILE_SIZE_BLKS
/u01/oradata/helen/control01.ctl NO 16384 430
/u01/oradata/helen/control02.ctl NO 16384 430
/u01/oradata/control03.ctl NO 16384 430

NOw,we have multiplexed the Control File When using SPFILE.

2 Multiplexing the control file when using PFILE

First of all, you should to know if your server is now using a PFILE ?

SQL> show parameter spfile; At here,we can get the conclusion that the server is now using a PFILE,cause the result of the value column is null.
NAME TYPE VALUE
spfile string

Maybe you are confused about the result of the above SQL command,but in fact it’s true.Next,
①  Shutdown the database.
②  Create Control Files at the target directory where you want multiplex and give the corrent names.
[oracle@Linux10g ~]$ cp /u01/oradata/helen/control03.ctl /u01/oradata/control04.ctl
③  Modify the PFILE ,to make it includes the Control Files which we have created just now.
Before we change the PFILE,it maybe looks like:
……
*.control_files=’/u01/oradata/helen/control01.ctl’,'/u01/oradata/helen/control02.ctl’,'/u01/o
radata/control03.ctl’
……
But after we’ve modified the file,it as :
……
*.control_files=’/u01/oradata/helen/control01.ctl’,'/u01/oradata/helen/control02.ctl’,'/u01/o
radata/control03.ctl’,'/u01/oradata/control04.ctl’
……
④   startup the database
SQL> startup pfile=’/u01/app/oracle/dbs/pfilehelen.ora’;

⑤ Identifying our Control File again,to see if  it works correctly.

SQL> select * from v$controlfile;

STATUS NAME IS_ BLOCK_SIZE FILE_SIZE_BLKS
/u01/oradata/helen/control01.ctl NO 16384 430
/u01/oradata/helen/control02.ctl NO 16384 430
/u01/oradata/control03.ctl NO 16384 430
/u01/oradata/control04.ctl NO 16384 430
Yep,It’s great.We can multiplex Oracle Control File weather the server is used a SPFILE or a PFILE.


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Comments

good job

Comment by banping on October 19, 2009 @ 16:15

Thank you.I will continue to write more and more articles to log my experiences.
BTW: banping, you are the one,you are the first one who commented on my site.

Comment by Asher on October 19, 2009 @ 19:38
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