Rack servers are a general-purpose machine that can be configured to support a wide range of requirements. What is a Rack Server? Rack servers in an EIA 19″ rackĪ rack server, or rack-mounted server, is any server that is built specifically to be mounted within a server rack. This article will serve as a quick start guide to both servers to provide a better understanding of each piece of equipment. The two most commonly used servers in the data center industry are blade servers and rack servers.