How to Check Whether Oracle Binary/Instance is RAC Enabled and Relink Oracle Binary in RAC [ID 28478

Goal

Fix

To check whether Oracle binary is RAC enabled:

To check whether a running instance is a RAC instance :

Steps to relink oracle binary with RAC option:

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Applies to:

Oracle Server - Enterprise Edition - Version 9.2.0.1 to 11.2.0.3 [Release 9.2 to 11.2]
Information in this document applies to any platform.

Goal

This note is to check whether Real Application Clusters(RAC) option is linked into Oracle binary and whether a database instance is a RAC instance, and how to relink Oracle binary in RAC environment.

Fix

To check whether Oracle binary is RAC enabled:

As ORACLE_HOME owner:

On Linux/UNIX except AIX:

  ar -t $ORACLE_HOME/rdbms/lib/libknlopt.a|grep kcsm.o

On AIX:

  ar -X32_64 -t $ORACLE_HOME/rdbms/lib/libknlopt.a|grep kcsm.o

If above command does not return anything, RAC option is not linked in. A RAC enabled oracle binary should return "kcsm.o".

To check whether a running instance is a RAC instance :

Multiple options here:

1. Check sqlplus banner (Applicable to Windows):

$ORACLE_HOME/bin/sqlplus / as sysdba

SQL*Plus: Release 11.1.0.6.0 - Production on Fri Dec 26 12:11:13 2008
Copyright (c) 1982, 2007, Oracle. All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options

A RAC instance will show "Real Application Clusters" option in the banner.


2. Check whether lmon background process exists for the instance

ps -ef| grep lmon | grep <ORACLE_SID>
oracle   627     1  0   Apr 15     ?  1:02 ora_lmon_racdb1

Only RAC instance has lmon background process.


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.

Steps to relink oracle binary with RAC option:

Execute the following on all nodes where the ORACLE_HOME exists:

1. Log in as the ORACLE_HOME owner.

2. Stop all resources (database, listener, ASM etc) that's running from the home. When stopping database, use NORMAL or IMMEDIATE option.

3. If relinking 11gR2 Grid Infrastructure home, unlock GI home as root: $GRID_HOME/crs/install/rootcrs.pl -unlock

4. Execute the following to relink:

  cd $ORACLE_HOME/rdbms/lib
  make -f ins_rdbms.mk rac_on ioracle

If interconnect is infiniband and RDS protocol is being used instead of UDP:

  cd $ORACLE_HOME/rdbms/lib
  make -f ins_rdbms.mk ipc_rds ioracle

Caution: confirm infiniband interconnect and RDS protocol before executing it 
Note: If you are changing more than 1 home, repeat the make command for all homes. 

5. If relinking 11gR2 Grid Infrastructure home, lock GI home as root: $GRID_HOME/crs/install/rootcrs.pl -patch