### Servers and Sites

The Servers and Sites configuration attributes allow for centralized configuration management of sites and servers for the entire deployment.

Multiple (two or more) OpenSSO instances can be deployed on at least two different host servers. For example, you might deploy two instances on one server and a third instance on another server. Or you might deploy all instances on different servers. You can also configure the OpenSSO instances in session failover mode, if required for your deployment.

One or more load balancers route client requests to the various OpenSSO instances. You configure each load balancer according to your deployment requirements (for example, to use round-robin or load average) to distribute the load between the OpenSSO instances. A load balancer simplifies the deployment, as well as resolves issues such as a firewall between the client and the back-end OpenSSO servers. You can use a hardware or software load balancer with your OpenSSO deployment. All OpenSSO instances access the same Directory Server.