Enabling failover in a multiple node Oracle RAC database cluster (UNIX/Linux)

About this task

To enable failover in a multiple node Oracle RAC database cluster in UNIX/Linux, do the following:

Procedure

Navigate to the <INSTALL_DIR>/properties directory, where you will modify the sandbox.cfg and customer_overrides.properties files.
Note: You might need to create the customer_overrides.properties file, which is just for customizations and is not automatically created during an installation. .
In the sandbox.cfg file, add a new property for ORACLE_JDBC_URL which contains the Oracle RAC connection URL.
The following example shows the suggested URL form. This example shows how the information is organized, but the property value must be one string of text, starting with ORACLE_JDBC_URL=. Your database administrator (DBA) can modify this URL as needed.
```
   jdbc:oracle:thin:@
      (DESCRIPTION=
         (ADDRESS_LIST=
            (FAILOVER=ON)
            (LOAD_BALANCE=ON)
            (ADDRESS=(PROTOCOL=TCP)(HOST=myhost1)(PORT=1521))
            (ADDRESS=(PROTOCOL=TCP)(HOST=myhost2)(PORT=1521))
           )
           (CONNECT_DATA = (SERVER = DEDICATED)(SERVICE_NAME = myservicename))
   )
```
In the customer_overrides.properties file, add the readTimeout property to all Oracle database pools. These values override the corresponding values in the jdbc.properties file.
- jdbcService.oraclePool.prop_jdbc.readTimeout=90000
- jdbcService.oraclePool_local.prop_jdbc.readTimeout=90000
- jdbcService.oraclePool_NoTrans.prop_jdbc.readTimeout=90000
- jdbcService.oraclePool_NoTrans.prop_jdbc.readTimeout=90000
  The readTimeout value will require tuning. If the value is too low, long-running queries in the system will be interrupted. If the value is too high, recovery when a RAC node fails will be delayed.
Run the setupfiles.sh command from the <INSTALL_DIR>/bin directory.
Set the propagation delay on the RAC server to 0.