Controlfile Multiplexing and De-Multiplexing In Oracle12c

Controlfile Multiplexing and De-Multiplexing In Oracle12c

In this article we will learn what controlfile contains,How to perform controlfile Multiplexing and De-Multiplexing .

Control file :

  • Controlfile is a Physical file.
  • Controlfile is a small binary file which contains the current physical structure of database.
  • Control file contains all the crucial information of database like

–>DBname and ID

–>Name  & locations of datafiles

–>SCN# Number

–>Name  & locations of redolog files

–>Rman backup informationArchive information

–>Time stamp of DB creation

  • Control file is used to start the database.
  • The size of control file is in lower MB’s
  • We can multiplex the control files to 8 different location(Min-1   Max-8)
  • We will give .ctl extension for the controlfile ,but the extension is not mandatory.It is understanding and only for our purpose.

 

Control file Multiplexing :

As a DBA, you know that control files play a very important role in oracle database.

If the control files are corrupt, can you start your database?

No, you can’t do it. So what should be done to avoid such type of corruption?

As a DBA, it’s your responsibility to multiplex control files to protect your organization in case of possible data loss due to media failure or control file corruption.

Creating a copy of controlfile in  a new location with a new name .

Steps for Multiplexing controlfile.

Step 1 :

Connect to database and check for controlfile location .

Or else we can check using Show Parameter 

Step 2 :

Shutdown the database and create new physical location If we dont have existing location

Creating new physical location If we dont have existing location

Step 3 :

Copy the Current Controlfile to Another Directory Location:

Step 4 :

Go to pfile location and add new location to control_files parameter

Step 5 :

Startup the database  and check control_file parameter

 

De-Multiplexing controlfiles :

Need to repeat same steps but in reverse order

Step 1:

Check controlfile location and Shutdown the database

Step 2 :

Go top pfile and remove path of unwanted controlfile location

 

Step 3 :

Connect to sqlplus and start the database

Step 4 :

Check controlfile location

 

Thank you ….

Note: Please test scripts in Non Prod before trying in Production.
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