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Oracle RAC: ON and OFF

Disabling Oracle's RAC options may be necessary when testing the Oracle Database 10g. Steps are outlined in this excerpt from "Oracle Database 10g: Real Application Clusters Handbook."

Published: 09 May 2007

Oracle's RAC: ON and OFF

In some cases, you may want to disable the RAC options for testing purposes -- perhaps to run a benchmark or convert the RAC binaries to single instance binaries. In such a case, you can use the following procedure to convert the RAC installation to non-RAC. Disabling and enabling RAC options are available only for UNIX platforms. Windows installations do not support relinking binaries with RAC ON and 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/lib: cd $ORACLE_HOME/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/lib:
    4. cd $ORACLE_HOME/lib
  4. Run the following make command to relink the Oracle binaries without the RAC option:
    5. 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:
    6. 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.

Use the following table of contents to navigate to chapter excerpts or click here to view RAC Troubleshooting in its entirety.


Oracle Database 10g: Real Application Clusters Handbook
  Home: Oracle RAC troubleshooting: Introduction
  1: Oracle RAC: Log directory structure in cluster ready services
  2: Oracle RAC: Log directory structure in Oracle RDBMS
  3: Oracle RAC and the Lamport algorithm
 4: Oracle RAC: ON and OFF
  5: Oracle RAC: Database performance issues
  6: Oracle RAC: Debugging node eviction issues
  7: Oracle RAC: Member voting
  8: Oracle RAC: Cluster reconfiguration steps
  9: Oracle RAC: Debugging CRS and GSD using DTRACING
About the book:   
Oracle Database 10g: Real Applications Clusters Handbook Learn to implement Oracle real application clusters from the ground up. Maximize database availability, scalability, and efficiency. Find RAC concepts, administration, tuning, and troubleshooting information. You'll learn how to prepare and create Oracle RAC databases and servers, and automate administrative tasks. You'll also get full coverage of cutting-edge Oracle RAC diagnostic tools, backup and recovery procedures, performance tweaks and custom application design strategies. Buy this book at McGraw-Hill/Osborne
About the author:   
K Gopalakrishnan is a senior principal consultant with the Advanced Technology Services group at Oracle Corporation, specializing exclusively in performance tuning, high availability, and disaster recovery. He is a recognized expert in Oracle RAC and Database Internals and has used his extensive expertise in solving many vexing performance issues all across the world for telecom giants, banks, financial institutions, and universities.

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