Using Oracle Real Application Clusters (RAC) for High Availability

Load balancing

Oracle RAC supports initial connection time load balancing and runtime connection load balancing. However, running Sterling B2B Integrator with load balancing turned on is likely to result in performance issues.

On the client side (JDBC URL), you should set the parameter LOAD_BALANCE to OFF.

On the server side, turn off load balancing on the database service.

SCAN (Single Client Access Name)

Available beginning in Oracle RAC 11g R2, SCAN allows you to set up RAC failover without specifying nodes. Using traditional RAC in Sterling B2B Integrator, you configure the JDBC URL to name an initial node and a failover node. With SCAN, you configure the JDBC URL so that SCAN selects the initial node and fails over to the other available node.

A benefit to using SCAN over traditional RAC is that you do not need to update the URL when a node name changes. There is, however, a potential performance degradation as SCAN searches for an available node.

High availability (Failover)

Oracle RAC supports high availability by eliminating the dependence on a single server, where the chances of database downtime are more due to hardware failure.

• Initial connection time failover

  In initial connection time failover, the database node availability is determined while establishing the connection. The connection is established with the available database node. However, if a database node goes down while a transaction is in progress, the transaction will fail and throw an SQLException error, and a new connection will be established with the available node.

  Initial connection time failover can be configured on the JDBC multi-instance URL on the client side by setting this parameter:

  FAILOVER=ON

  Sterling B2B Integrator supports two-node Oracle RAC setup.

  To establish initial time connection failover in Sterling B2B Integrator, perform the following tasks:

  1. Configure the following properties in ASI node and in the customer_overrides.properties.in file in containers. You can set values for these properties (in milliseconds) that are suitable for your operating environment.

     Setting a value too low would result in genuine SQL queries getting terminated before they have a chance to be processed and return the dataset. A value too high means that the application threads are holding connections which are waiting on a query timeout for that duration and are not available for other tasks. This could result in lower throughput. An optimum setting depends on the customer's environment.

     jdbcService.oraclePool.prop_oracle.jdbc.ReadTimeout=<milliseconds>
     jdbcService.oraclePool_local.prop_oracle.jdbc.ReadTimeout=<milliseconds>
     jdbcService.oraclePool_NoTrans.prop_oracle.jdbc.ReadTimeout=<milliseconds>
     jdbcService.oracleUIPool.prop_oracle.jdbc.ReadTimeout=<milliseconds>
     jdbcService.oracleArchivePool.prop_oracle.jdbc.ReadTimeout=<milliseconds>

  2. Perform one of the following:
     • (UNIX or Linux®) From the install_dir/install/bin directory, run setupfiles.sh.
     • (Windows) From the install_dir\install\bin directory, run setupfiles.cmd.
  3. Restart the ASI and container JVMs to apply the changes.

High availability (Failover), continued

• Runtime connection failover

  When one Oracle RAC node goes down, the active connections from the node that went down will failover to the active node. When the node that went down is up and running again, the connections are not redistributed. You can redistribute the connection pools by setting lifespan parameter to a value greater than 0, which ensures that connection pools are terminated after the lifespan value is met and load balancing occurs when new connections are established. However, configuring a low value lifespan may lead to connections being terminated quickly thereby losing the benefit of connection pool.

  To override all the Oracle pools lifespan to a value greater than 0, set the following value in the customer_overrides.properties.in file:

  jdbcService.<oraclepool>.lifespan=180000

Sterling B2B Integrator does not support Fast Connection Failover (FCF).

Sterling B2B Integrator does not support Transparent Application Failover (TAF).