Horizontal scaling is achieved in the OpenSSO Enterprise environment by connecting multiple host servers so they work as one unit. A load-balanced service is considered horizontally scaled because it increases the speed and availability of the service. Vertical scaling, on the other hand, is increasing the capacity of existing hardware by adding resources within a single host server. The types of resources that can be scaled include CPUs, memory, and storage. Horizontal scaling and vertical scaling are not mutually exclusive; they can work together for a deployment solution. Typically, servers in an environment are not installed at full capacity, so vertical scaling is used to improve performance. When a server approaches full capacity, horizontal scaling can be used to distribute the load among other servers.