Deployment Planning Guide > Load Balancing and Resilient Processing Planning >

About Load Balancing

Load balancing distributes workload across multiple servers. Each server runs an instance of the service you want to load-balance. Load balancing also provides failover. Should one server fail, then requests are automatically routed to the remaining servers.

Load balancing can be used when the Siebel Enterprise Server has two or more Siebel Servers that are not clustered. Load balancing is the preferred method for providing high availability for the following server components:

• Application Object Managers (AOMs)
• Siebel Configurator (uses own load balancing method)
• Siebel EAI, whenever possible

Prior to Siebel 7.7

Prior to Siebel 7.7, Siebel Systems implemented server load balancing using a third-party software product, Resonate Central Dispatch. When multiple Siebel Servers ran the same Application Object Manager, Central Dispatch distributed server requests across the Siebel Servers. Siebel Servers were integrated with Central Dispatch to maintain session continuity.

Siebel 7.7 and Later

For Siebel 7.7 and later releases, Siebel supports two methods for implementing Siebel Server load balancing:

• Siebel-provided load balancing, called Siebel load balancing. A load balancing module is built into the Siebel Web Server Extension (SWSE). This module provides software-based load balancing for Siebel Servers. Siebel load balancing can be used instead of third-party HTTP load balancers.
• Siebel Systems has certified a number of third-party, hardware-based HTTP load balancers for use in a Siebel deployment. For a list of these, see System Requirements and Supported Platforms on Siebel SupportWeb.

  Certification means Siebel Systems has tested interoperability with the load balancer extensively, and specific configuration instructions are available. Siebel Technical Support will work with customers on configuration and interoperability issues specific to Siebel deployments.

  If customers are using a noncertified load balancer and encounter load balancing issues, they should contact the third-party load balancer vendor directly. If a load balancing or connectivity issue is encountered, customers should try to reproduce the issue with Siebel load balancing to isolate the cause. It is recommended that you use a certified load balancer to minimize potential compatibility issues. Although Siebel applications are designed to work with standard, third-party HTTP applications, customers should perform compatibility testing before using an uncertified load balancer.

  Configuration and troubleshooting information for third-party load balancers is available on Siebel SupportWeb as Technical Notes.

Siebel Connection Broker. On each Siebel Server, the Siebel Connection Broker (SCBroker), provides intraserver load balancing. SCBroker distributes server requests across multiple instances of Application Object Managers running on the server.

Resonate support discontinued. Automatic registration of Resonate rules is no longer supported. Siebel Server parameters for Resonate registration are no longer supported. For Siebel Servers, Resonate is classified as an uncertified third-party load balancer.

Figure 5 shows an example of third-party load balancing.

Figure 5.  Example of Third-Party Load Balancing