Convert a standalone database to Oracle RAC by using rconfig

Introduction

Have you ever wondered how to convert a standalone database to an Oracle®; Real Application Clusters (RAC) database?

You can use rconfig, a non-interactive command-line utility, to convert asingle-instance database to a RAC database. The utility reads the values provided under the ConvertToRAC.xml file.

The $ORACLE_HOME/assistants/rconfig/sampleXMLs directory has two templates, ConvertToRAC\_AdminManaged.xml and ConvertToRAC\_PolicyManaged.xml which you can use to convert a single-instance database to RAC admin or policy-managed database, respectively. This blog explores the  admin-managed RAC conversion, although the same approach applies to a policy-managed
database.

The following image shows a sample ConvertToRAC_AdminManaged.xml file::

Prerequisites for using rconfig 

Before you use rconfig, consider the following prerequisites::

•    Use Oracle Database version 10g R2 or later.
•    Configure Clusterware and have it running on all the nodes.
•    Install Oracle RAC RDBMS on all the nodes.
•    Make sure that shared storage, either Oracle Cluster File System or Automatic
•   Storage Management (ASM), is available and accessible from all the nodes.
•    Verify that the standalone database and RAC are the same database version.
•    You need an active ASM instance across the nodes and the database running on one of the local nodes.

Steps for conversion to RAC 

Use the following steps to convert your standalone database to RAC.

Step 1:  Set the parameters

You need to set the following parameters in ConvertToRAC_AdminManaged.xml:

The `convert verify` option in ConvertToRAC.xml has three options:

-    Convert verify="YES: rconfig performs prerequisite checks followed by RAC conversion.
-    Convert verify="NO: rconfig performs RAC conversion without the prerequisite checks.
-    Convert verify=ONLY: `rconfig` performs only the prerequisite checks and takes no other action

Step 2: Perform the prerequisite checks.

Run the following command to run the `convert_verify="ONLY”` option to fix any
errors:

    $ cd $ORACLE_HOME/assistants/rconfig/sampleXMLs
    $ $ORACLE_HOME/bin/rconfig ConvertToRAC_racdb.xml

Example:

  [oracle@racnode1 sampleXMLs]$ rconfig ConvertToRAC_racdb.xml
    <?xml version="1.0" ?>
    <RConfig version="1.1" >
      <ConvertToRAC>
        <Convert>
          <Response>
            <Result code="0" >
              Operation Succeeded
            </Result>
          </Response>
          <ReturnValue type="object">
            There is no return value for this step
          </ReturnValue>
        </Convert>
      </ConvertToRAC>
    </RConfig>
Execute rconfig for RAC conversion

When you run the following commands to execute `rconfig` to convert the database, make sure you update the parameter to `convert_verify="YES"`.
`rconfig` performs the conversion and the verification.

    $ cd $ORACLE_HOME/assistants/rconfig/sampleXMLs
    $ $ORACLE_HOME/bin/rconfig ConvertToRAC_racdb.xml

Run the following command to monitor alerts in the `rconfig` log on the standalone database and the new RAC database:

    $ tail -f /ora/app/oracle/cfgtoollogs/rconfig/rconfig*.log

Example:

    [oracle@racnode1 sampleXMLs]$ rconfig ConvertToRAC_racdb.xml
    Converting Database "SOATEMP" to Cluster Database.
    Target Oracle Home: /u01/app/oracle/product/11.2.0/dbhome_1. Database Role: PRIMARY.
    Setting Data Files and Control Files
    Adding Database Instances
    Adding Redo Logs
    Enabling threads for all Database Instances
    Setting TEMP tablespace
    Adding UNDO tablespaces
    Adding Trace files
    Setting Fast Recovery Area
    Updating Oratab
    Creating Password file(s)
    Configuring Listeners
    Configuring related CRS resources
    Starting Cluster Database
    <?xml version="1.0" ?>
    <RConfig version="1.1" >
      <ConvertToRAC>
        <Convert>
          <Response>
            <Result code="0" >
              Operation Succeeded
            </Result>
          </Response>
          <ReturnValue type="object">
            <Oracle_Home>
              /u01/app/oracle/product/11.2.0/dbhome_1
            </Oracle_Home>
            <Database type="ADMIN_MANAGED"  >
              <InstanceList>
                <Instance SID="RACDB1" Node="racnode1"  >
                </Instance>
                <Instance SID="RACDB2" Node="racnode2"  >
                </Instance>
              </InstanceList>
            </Database>
          </ReturnValue>
        </Convert>
      </ConvertToRAC>
    </RConfig>
 

Step 4: Verify the conversion

Run the following commands to verify the log, check the RAC database status, and check the datafile status.

Note: If the standalone database was non-ASM, it is now ASM.

    $ srvctl status database -d racdb
    Check by login to sqlplus
    SQLPLUS> select * from gv$instance;
    SQLPLUS> select file_name from dba_data_files;

Step 5: Modify tnsentry

Modify `tnsentry` on the local node with `scan-name` and copy it to all other nodes

 Conclusion

`rconfig` performs automated RAC conversions and saves the time and effort of the multiple manual configuration steps. It also takes an RMAN backup in case a non-ASM to ASM conversion is required, which might increase the downtime for large databases. You can tune this by allocating multiple I/O channels for the backup. If the standalone and target RAC database are on ASM, you can use rconfig as a quick solution for the RAC conversion.