Multiplexing Control Files

Multiplexing Control Files using init.ora

Multiplexing means keeping the copy of same control files on different disk drivers and idealy on different controllers too. To multiplex control files, copy the control file to multiple locations and change the CONTROL_FILES parameter in the text based initialization file init.ora to include all contro files names.

Step to multiplex.
1. Shut down the database
SQL> shutdown normal
2. Copy the control file to more locations using operating system command.
$cp u02/oradata/ord/control01.ctl  u05/oradata/ord/control02.ctl

3. Change the initialization parameter to include new file in the parameter CONTROL_FILES
CONTROL_FILES = ('u02/oradata/ord/control01.ctl','u03/oradata/ord/control01.ctl','u04/oradata/ord/control01.ctl','u05/oradata/ord/control01.ctl')
4. Start the instance
SQL> startup normal;

 Multiplexing Control Files using spfile

Steps are similar as the above using init.ora file. The major difference is how CONTROL_FILES parameter is changed.

1. Alter System set CONTROL_FILES = 'u02/oradata/ord/control01.ctl','u03/oradata/ord/control01.ctl','u04/oradata/ord/control01.ctl','u05/oradata/ord/control01.ctl' scope = spfile
2. Shut down the instance
shutdown normal;
3. Copy the control file to more locations using operating system command.
$cp u02/oradata/ord/control01.ctl  u05/oradata/ord/control02.ctl
4. startup;