The 'U' in any server description is short for "RU" which stands for Rack Unit -- this is the standardized designation for the form factor of the server: 1U = 1. 75" in height or thickness. Important: U describes height only, but a server's real "capabilities" are also determined by chassis depth, internal layout, airflow, rails, power, and expansion (PCIe/risers, NVMe. Devices designed to fit into rackmount server cabinets come in a range of heights, from 1U to 4U. A 1U panel is 1 Rack Unit tall, a 2U is 2 Rack Units tall and so on. A 42U rack cabinet has the capacity to fit 42 1U pieces of equipment or 24 2U devices. Best For. The 1U is the slimest choice in the. A “U” or rack unit is a measurement of the height of a piece of computer or network gear that is designed to fit into a standard 19″ or 23″ rack. 45 mm), the "U" unit ensures that every component, whether it's a 1U server, a 2U storage unit, or a 42U full-height rack, fits together perfectly.
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