How to enable/disable RAC (ON/OFF)

Use the following steps to disable RAC (known as RAC OFF):

1. Log in as the Oracle software owner (which is typically the UNIX account oracle) in all nodes.
2. Shut down all the instances from all the nodes using a NORMAL or IMMEDIATE option.
3. Change the working directory to $ORACLE_HOME/rdbms/lib: cd $ORACLE_HOME/rdbms/lib
4. Run the following make command to relink the Oracle binaries without the RAC option: make -f ins_rdbms.mk rac_off

This normally runs for few minutes and should not pose any errors.
5. . Now relink the Oracle binaries: make -f ins_rdbms.mk ioracle

Now the Oracle binaries are relinked with the RAC OFF option. You may have to edit the init.ora or SPFILE parameters accordingly. If errors occur in step 4, you may need to contact Oracle Support and log a service request with the trace and log files.

Use the following steps to enable RAC (known as RAC ON):

1. Log in as the Oracle software owner (typically the UNIX account oracle) in all nodes.
2. Shut down all the instances from all the nodes using a NORMAL or IMMEDIATE option.
3. Change the working directory to $ORACLE_HOME/rdbms/lib:
4. cd $ORACLE_HOME/rdbms/lib Run the following make command to relink the Oracle binaries without the RAC option:
make -f ins_rdbms.mk rac_on

This normally runs for a few minutes and should not pose any errors.
5. Now relink the Oracle binaries:
make -f ins_rdbms.mk ioracle

Now the Oracle binaries are relinked with the RAC ON option. You may need to edit the init.ora or SPFILE parameters accordingly. If any errors occur in step 4, you may need to contact Oracle Support and log a service request with the trace and log files.