Rac On / Rac Off – Oracle Does Not Make It Easy

Working on task to convert RAC database to Single Instance database.

There are so many options and which to chose and is the best?

make -f ins_rdbms.mk rac_off and make -f ins_rdbms.mk ioracle was used.

Only issue is process ora_lmon_racdb1 is running.

Here are options and how to validate.

Rac On / Rac Off – Relinking the RAC Option (Doc ID 211177.1)

RAC OFF

1. Login as the Oracle software owner and shutdown all database instances on all nodes in the cluster.
2. cd $ORACLE_HOME/rdbms/lib
3. make -f ins_rdbms.mk rac_off
   If this step did not fail with fatal errors, proceed to step 4.
4. make -f ins_rdbms.mk ioracle

Note: If these steps fail with a Fatal Error, then you will need to open a Service Request and submit these errors to Oracle Support for analysis.

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How to Check Whether Oracle Binary/Instance is RAC Enabled and Relink Oracle Binary in RAC (Doc ID 284785.1)

On Linux/UNIX except AIX:
ar -t $ORACLE_HOME/rdbms/lib/libknlopt.a|grep kcsm.o

To check whether a running instance is a RAC instance :

Multiple options here:

1. Check sqlplus banner (Applicable to Windows):
   To check whether a running instance is a RAC instance :
   With the Partitioning, Real Application Clusters, OLAP and Data Mining options
2. Check whether lmon background process exists for the instance
3. Check cluster_database parameter
   SQL> show parameter cluster_database

Output “true” means it’s RAC instance but this is not reliable as a RAC instance may have cluster_database set to false during maintenance period.