In this chapter, system failure refers to a hardware or process failure at the OpenSSO Enterprise server, at the Policy Agent, or at a load balancer. Hardware fails due to a mechanical problem or power outage. A web container application crashes causing OpenSSO Enterprise to become inaccessible. These are examples of system failure. Whenever possible, you should install redundant OpenSSO Enterprise servers, OpenSSO Policy Agents, and load balancers to serve as backups, or to fail over to, in the event of a system failure. This helps to ensure that no single point of failure exists in your deployment. Load balancers distribute the workload among OpenSSO Enterprise servers. If a Policy Agent fails, requests are redirected to another Policy Agent. If server hardware fails, requests are routed to other server hardware. Without system failover, a single hardware failure or process failure can cause OpenSSO Enterprise downtime.