C Oracle RAC: Other Considerations

C.4.1.1 Backing Up the Original Single-Instance Database

Use Database Configuration Assistant to create a preconfigured image of the single-instance database. To do this, perform the following:

1. Start Database Configuration Assistant with the DBCA command.

2. On the Welcome screen, select Manage Templates.

3. Select Create a database template.

4. Select the database name from Database Name.

5. Enter the template name and description and template data file location in Template Name. Use the database name as the default template name.

6. Click Finish.

Database Configuration Assistant generates two files, a database structure file (template_name.DBC) and a database preconfigured image file (template_name.DFB). These files are generated by default in the ORA_ROOT:[ASSISTANTS.DBCA.TEMPLATES] directory.

C.4.1.2 Performing the Preinstallation Steps

Perform the preinstallation steps as documented in this book. Then, set up shared storage by referring to Section 2.13, "Creating Directories for Oracle Database or Recovery Files".

C.4.1.3 Setting Up the Cluster

If have not already done so, create a cluster with the required number of nodes according to the vendor documentation. Once you have configured all the nodes in the cluster, install Oracle Clusterware by following the procedure in Section 5.9, "Installing Oracle Clusterware".

C.4.1.4 Copying the Preconfigured Database Image

This includes copying the database structure *.DBC file and the database preconfigured image *.DFB file to a temporary location on the node in the cluster from which you plan to run Database Configuration Assistant. These files are created by Database Configuration Assistant. For more information, refer to Section C.4.1.1, "Backing Up the Original Single-Instance Database".

C.4.1.5 Installing Oracle Database with Oracle RAC

Perform the following tasks to install Oracle Database 10g with Oracle RAC:

1. Run Oracle Universal Installer.

2. Select Cluster Installation Mode on the Specify Hardware Cluster Installation screen, and select the nodes to include in the Oracle RAC database.

3. On the Database Configuration Types screen, select the Advanced install type.

   After installing the Oracle software, Oracle Universal Installer runs the postinstallation configuration tools, such as the Oracle Network Configuration Assistant, Database Configuration Assistant, and so on.

4. On the Database Configuration Assistant Template Selection screen, use the template that you copied to a temporary location in the Section C.4.1.4, "Copying the Preconfigured Database Image" procedure. Use the browse option to select the template location.

5. After creating the RAC database, Database Configuration Assistant displays the Password Management screen. On this screen, change the passwords for the privileged users with the SYSDBA and SYSOPER roles. Once Database Configuration Assistant exits, the conversion process is complete.

C.4.2.1 Single Instance on a Cluster Running from a Cluster-Enabled Oracle Home

Perform the following tasks to convert a single-instance database on a cluster running from a cluster installed Oracle home.

1. Use Database Configuration Assistant to create a preconfigured image of the single-instance database as described in Section C.4.1.1, "Backing Up the Original Single-Instance Database". To perform the conversion manually, shut down the single-instance database.

2. To add nodes to the cluster, add and connect these nodes to the cluster as described in Section C.4.1.2, "Performing the Preinstallation Steps". Ensure that all these nodes can access the shared storage.

3. From one of the newly added nodes, configure the listeners on the additional nodes using the Oracle Network Configuration Assistant. Select the same port number and protocol that you used on the existing node. If the Oracle Network Configuration Assistant displays the existing node on the Node List screen, then do not select this node because the listener is already configured on it.

4. Convert the database using one of the following procedures:

   • Section C.4.2.2, "Automated Conversion"

   • Section C.4.2.3, "Manual Conversion"

C.4.2.2 Automated Conversion

The following steps describe the procedure to automatically convert the database:

1. If you created the preconfigured image of the single instance database as described in Section C.4.1.1, "Backing Up the Original Single-Instance Database", then use Database Configuration Assistant to complete the conversion to a Oracle RAC database.

2. Start Database Configuration Assistant from the initial node. Select the names of the nodes that you want to include as part of the cluster database. On the Template Selection screen, select the preconfigured template that you create in Step 0. Enter the database name and respond to the remaining Database Configuration Assistant prompts.

After creating the Oracle RAC database, Database Configuration Assistant displays the Password Management screen. Change the passwords for database privileged users who have SYSDBA and SYSOPER roles. Once Database Configuration Assistant exits, the conversion process is complete.

C.4.2.3 Manual Conversion

Perform the following steps to manually convert the database:

1. Re-create the control files by running the CREATE CONTROLFILE SQL statement with the REUSE keyword, and specify MAXINSTANCES, MAXLOGFILES, and so on, as needed for the Oracle RAC configuration. The default MAXINSTANCES value is 32 (recommended).

2. Shut down the database instance.

3. If the single-instance database was using an SPFILE parameter file, then create a temporary PFILE from the spfile using the following SQL statement:

   CREATE PFILE='pfile_name' FROM SPFILE='spfile_name'
   
   

4. Set the CLUSTER_DATABASE parameter to TRUE. Set the INSTANCE_NUMBER parameter to a unique value for each instance, using the sid.parameter=value syntax.

   If you optimized memory usage on the single-instance database, adjust the size of the System Global Area (SGA) to avoid swapping and paging when you convert to Oracle RAC. This is because Oracle RAC requires about 350 bytes for each buffer to accommodate the Global Cache Service (GCS). For example, if you have 10,000 buffers, Oracle RAC requires about 350 * 10,000 bytes more memory. Therefore, adjust the size of the SGA by changing the DB_CACHE_SIZE and DB_nK_CACHE_SIZE parameters accordingly.

5. Start the database instance using the PFILE created in Step 3.

6. If the single-instance database was using automatic undo management, then create an undo tablespace for each additional instance using the CREATE UNDO TABLESPACE SQL statement.

7. Create redo threads that have at least two redo logs for each additional instance. Enable the new redo threads by using an ALTER DATABASE SQL statement. Then shut down the database instance.

8. Copy the Oracle password file from the initial node, or from the node on which you are working, to the corresponding location on the additional nodes on which the cluster database will have an instance. Ensure that you replace the ORACLE_SID name in each password file for each additional instance.

9. Add REMOTE_LISTENER=LISTENERS_DB_NAME and sid.LOCAL_LISTENER=LISTENER_SID parameters to the PFILE.

10. Configure the Oracle Net Services entries for the database and instances and address entries for the LOCAL_LISTENER for each instance and REMOTE_LISTENER in the TNSNAMES.ORA file, and copy it to all nodes.

11. Create the SPFILE from the PFILE as described in Section 6.12.2, "Procedures for Upgrading to the Server Parameter File".

12. Create the ORA_ROOT:[DBS]INITsid.ora file that contains the following entry:

    spfile='spfile_path_name'
    
    

    where spfile_path_name is the complete path name of the SPFILE.

13. Add the configuration for the Oracle RAC database and its instance-to-node mapping using the SRVCTL utility.

14. Start the Oracle RAC database using SRVCTL.

    After starting the database with SRVCTL, the conversion process is complete. For example, you can run the following SQL statement to see the status of each instance in the Oracle RAC database:

    SELECT * FROM v$active_instances
    

C.4.2.4 Single-Instance Database on a Cluster Running from a Oracle RAC-Disabled Oracle Home

This installation is possible if you performed a one-node cluster (with Oracle RA C) installation but later disabled the Oracle RAC feature by unlinking it from the ORACLE binary before creating the single-instance database. However, you can also select the local, noncluster selection on the Node Selection screen to create a single-instance home on a cluster that is not Oracle RAC-enabled.

Perform the following procedures to convert this type of single-instance database to a Oracle RAC database:

1. On the cluster node where the single-instance database is running, run Step 0 of Section C.4.2.1, "Single Instance on a Cluster Running from a Cluster-Enabled Oracle Home".

2. Set default to ORA_ROOT:[RDBMS.BIN].

3. Relink the ORACLE binary as follows:

   • Shut down the database if it is already running.

   • Remove the ORACLE binary by running the following command:

     $ REMORACLE
     
     

   • Create the single-instance Oracle image by running the following command:

     $ @ORA_ROOT:[BIN]RELINK ORACLE
     
     

   • Run the following command:

     $ INSORACLE
     
     

4. Continue with Step 2.

C.4.2.5 Single-Instance Database on a Cluster Running from a Noncluster-Installed Oracle Home

This installation is only possible if you selected the local installation option on the Specify Hardware Cluster Installation screen during an Oracle Database 10g installation.

To covert this database to a RAC database, perform the procedures described under the following headings:

• Section C.4.1.1, "Backing Up the Original Single-Instance Database"

• Section C.4.1.2, "Performing the Preinstallation Steps"

• Section C.4.1.3, "Setting Up the Cluster"

• Section C.4.1.5, "Installing Oracle Database with Oracle RAC"

  Ensure that you select a new Oracle home other than the one from which the single-instance database was running.