Converting Single instance to RAC instance Database (rconfig)

Converting Single instance to RAC instance Database

There are different ways to convert a single instance database to RAC.

·         Manual Method

·         Using rconfig (from 10gR2)

·         Using DBCA

·         Using grid control

Notes

-          Install Oracle Clusterware on all nodes you intend to have as cluster members.

-          Eventually patch the clusterware software (the clusterware version need to be equal or higher than the rdbms version) as well as the rdbms software

-          During the "Install Oracle Database 10g or 11g Software with Real Application Clusters", make sure that you select a new Oracle home other than the one from which the single-instance database was running in case the single-instance database is running on one of the systems. Upgrade the RAC RDBMS software to the same version as the original single-instance database.

-          Configure the cluster listener, i.e. configure the listener through netca from the new cluster RDBMS Home. Eventually stop the single instance listeners when they are running on one of the clustered nodes in case they are using the same listener ports. Ideally, use the 'LISTENER' as name for that listener.

-          Prior 11g R2, it is recommended to run the listener from the RDBMS home and from11gR2 it is recommended to run the listener from the Grid Infrastructure home.

-          Move datafiles, redo logs, control file to a shared location on the cluster or ASM.

Convert Single-Instance database to RAC using rconfig

rconfig is a command line tool introduced in Oracle Database 10g R2 to convert Single-Instance 10g R2 Database to RAC(Real Application Cluster)

rconfig is located at $ORACLE_HOME/bin/. rconfig takes in a xml input file and convert the Single Instance database whose information is provided in the xml. 

a sample xml can be found $ORACLE_HOME/assistants/rconfig/sampleXMLs/ConvertToRAC.xml

rconfig performs following steps :

• Migrate the database to ASM storage (Only if ASM is specified as storage option in the configuration xml file)
• Create Database Instances on all nodes in the cluster 
• Configure Listener and NetService entries
• Configure and register CRS resources 
• Start the instances on all nodes in the cluster.

Prerequisites before we use rconfig

Before you convert a single-instance database to a RAC database using rconfig, ensure that the following conditions are met for each cluster node that you intend to make a RAC database node:

• Oracle Clusterware 10g Release 2 (10.2) is installed, configured, and running.
• Oracle Real Application Clusters 10g Release 2 (10.2) software is installed.
• The Oracle binary is enabled for RAC.
• Shared storage, either Oracle Cluster File System or ASM, is available and accessible from all nodes.
• User equivalence exists for the oracle user.

Test rconfig before converting to RAC

Oracle 10g R2 Install has provided a sample rconfig input XML file called ConvertToRAC.xml at directory $ORACLE_HOME/assistants/rconfig/sampleXMLs. Make a copy of the sample XML file & make your own customised copy of input giving your Instance specific details. The Sample XML file includes comments to make understand how to edit each variable.

For testing purpose you need to modify the "Convert verify = "ONLY" option in the xml file.Then run the tool :

$ ./rconfig convert.xml

The Convert verify option in the ConvertToRAC.xml file has three options:

• Convert verify="YES": rconfig performs checks to ensure that the prerequisites for single-instance to RAC conversion have been met before it starts conversion
• Convert verify="NO": rconfig does not perform prerequisite checks, and starts conversion
• Convert verify="ONLY" : rconfig only performs prerequisite checks; it does not start conversion after completing prerequisite checks

Convert the single instance to RAC single database

·         As the oracle user, go to the directory $ORACLE_HOME/assistants/rconfig/sampleXMLs, and open the file ConvertToRAC.xml using a text editor.

·         Review the ConvertToRAC.xml file, and modify the parameters as required for your system. The XML sample file contains comments that provide instructions for how to configure the file.

·         Go to the directory $ORACLE_HOME/bin, and use the following command to run rconfig, where input.xml is the name of the XML input file you configured

$  ./rconfig  ConvertToRAC.xml

Below are list of parameters you should updated in XML file :

Verify does a precheck to ensure all pre-requisites are met, before the conversion is attempted. 

     Convert verify="YES" 

Specify current OracleHome of non-rac database for SourceDBHome 

     SourceDBHome-- ORACLE_HOME path --/n:SourceDBHome

Specify OracleHome where the rac database should be configured. It can be same as SourceDBHome

     TargetDBHome--ORACLE_HOME path--/n:TargetDBHome

Specify SID of non-rac database and credential. User with sysdba role is required to perform conversion
      SourceDBInfo SID="DBname"

ASMInfo element is required only if the current non-rac database uses ASM Storage

      ASMInfo SID="+ASM1" 
      Password—ASM sys password--/n:Password

Specify the list of nodes that should have rac instances running. LocalNode should be the first node in this nodelist. 

     Node name="Node1name" 
     Node name="Node2name"

Specify prefix for rac instances. It can be same as the instance name for non-rac database or different. The instance number will be attached to this prefix. 

     InstancePrefix—Instance_without_number--/n:InstancePrefix

Specify port for the listener to be configured for rac database.If port="", alistener existing on localhost will be used for rac database.The listener will be extended to all nodes in the nodelist 

     Listener port="Port_Number"

Specify the type of storage to be used by rac database. Allowable values are CFS|ASM. The non-rac database should have same storage type. 

     SharedStorage type="ASM" 

Specify Database Area Location to be configured for rac database.If this field is left empty, current storage will be used for rac database. For CFS, this field will have directory path.

     TargetDatabaseArea-- --/n:TargetDatabaseArea

Specify Flash Recovery Area to be configured for rac database. If this field is left empty, current recovery area of non-rac database will be configured for rac database. If current database is not using recovery Area, the resulting rac database will not have a recovery area. 

     TargetFlashRecoveryArea-- --/n:TargetFlashRecoveryArea 

rconfig log files located

 

rconfig log files are located at  $ORACLE_HOME/cfgtoollogs/rconfig

Also one important thing to note is that rconfig re-writes the log file everytime you run the rconfig tool. So make sure have a copy in case you want to refer to the results of earlier run

Restart Rconfig

 

After running RCONFIG in Convert verify="YES" Mode, if you get any fatal error(e.g. Disk space not available, Some issue with 10g Parameters, Shared Storage Issues) which exits the rconfig tool & stops the conversion. You can restart the rconfig tool again by running the command " $ ./rconfig convert.xml ". This will perform the clean-up operation on converted Instance or will delete the files created by earlier run. It again starts the process of conversion from start i.e. taking rman backup of Single Instance. After the conversion you can check the filesystem to verify if there is anything left from the previous failed run.