## Load Balancer Overview

The load balancer distributes the workload among multiple Application Server instances , increasing the overall throughput of the system. This section includes information on configuring the load balancer plug-in that is included with the Application Server. The plug-in works with the Sun Java System Web Server, as well as the Apache Web Server and Microsoft IIS. Hardware load balancers are also available. For more information, see Chapter 4, "Configuring HTTP Load Balancing," in Sun Java System Application Server 9.1 High Availability Administration Guide.

The load balancer also enables requests to fail over from one server instance to another. For HTTP session information to persist, configure HTTP session persistence. For more information, see Chapter 8, "Configuring High Availability Session Persistence and Failover," in Sun Java System Application Server 9.1 High Availability Administration Guide