Sun GlassFish Enterprise Server v2.1.1 Performance Tuning Guide

Configuring the Load Balancer

The Enterprise Server provides a load balancer plugin that can balance the load of requests among multiple instances which are part of the cluster.

Note –

The following section assumes that the server is tuned effectively to service incoming requests.

Enabling the Health Checker

The load balancer periodically checks all the configured Enterprise Server instances that are marked as unhealthy, based on the values specified in the health-checker element in the loadbalancer.xml file. Enabling the health checker is optional. If the health checker is not enabled, periodic health check of unhealthy instances is not performed.

The load balancer’s health check mechanism communicates with the application server instance using HTTP. The health checker sends an HTTP request to the URL specified and waits for a response. The status code in the HTTP response header should be between 100 and 500 to consider the instance to be healthy.

To enable the health checker, edit the following properties:

If the typical response from the server takes n seconds and under peak load takes m seconds, then set the timeout-in-seconds property to m + n, as follows: