A rack server, also called a rack-mounted server, is a computer dedicated to use as a server and designed to be installed in a framework called a rack. The rack contains multiple mounting slots called bays, each designed to hold a hardware unit secured in place with screws. A rack server has a low-profile enclosure, in contrast to a tower server, which is built into an upright, standalone cabinet.
A single rack can contain multiple servers stacked one above the other, consolidating network resources and minimizing the required floor space. The rack server configuration also simplifies cabling among network components. In an equipment rack filled with servers, a special cooling system is necessary to prevent excessive heat buildup that would otherwise occur when many power-dissipating components are confined in a small space.