Field Guide · hardware

Also known as: Rack-mount server

A rack server is a server built in a flat, standardized chassis that bolts into a 19-inch equipment rack, so many machines can be stacked densely in a cabinet.1

Overview

Height is measured in rack units (U), each 1.75 in (44.45 mm) tall.2 A 1U “pizza box” is the slimmest common server; 2U and 4U chassis trade density for more drive bays, expansion slots, and cooling. The 19-inch rack standard means servers, switches, and storage from different vendors share the same rails, power distribution, and cable management. Rack servers fill the cabinets of a data center, where airflow runs front-to-back through cold and hot aisles.

Where it fits

The rack server is the workhorse form factor for a dedicated server or a machine you place via colocation. When you need even higher density and shared power, a blade server packs more compute into the same space. Storage often rides alongside as network-attached storage. For most GopherTrunk users a rack server is overkill — a small box near the antenna is enough — but a rack machine is a natural home for long-term storage and serving of decoded data.

Sources

  1. 19-inch rack — Wikipedia, on the rack standard and mounting. 

  2. Rack unit — Wikipedia, on the U height unit. 

See also