If you have ever dealt with server furniture, you’ve definitely seen the “U” designation. A newbie may fall confused for the first time, since the designation is specific to the domain. Yet, experienced system administrators and the related staff know that the letter stands for the designation of a cabinet height. Below, we’re going to dedicate the article to a precise explanation of server rack measurement and its meaning.
Traditionally, any object has three dimensions, namely, depth, width, and height. We’re going to pay attention to the latter. The height of a server rack or cabinet is one of the key dimensions for furniture to ensure the perfect fitting of devices.
The Essence of “U” Designation
Firstly, let us clarify the question, “What is U in the server rack?” The “U” comes to designate the rack height. The measure was introduced by the Electronic Industries Alliance (“EIA”). Specifications were prescribed as EIA-310. The dimension was chosen to standardize furniture and simplify equipment fitting. Nowadays, the term is widely used not only in networking but also in telecom and business domains.
Answering the question “What is the size of a 1u rack?”, note that one U is equal to 1.75 inches, which is relevant to most modern servers. This height allows for accommodating one server per unit. Thus, it’s necessary to multiply the height to find the size in inches. For instance, 4U means 4 * 1,75 = 7 inches (ca. 18 cm).
Modern producers manufacture a great variety of models, due to which their heights differ a lot. Since network systems can be of different sizes and comprise from several dozen to a hundred components, their “U” dimensions range from 1U (for small systems) to 48U (for huge industrial-scale systems). According to the amount of Us, the following types of racks are distinguished:
1. Full rack (42U-48U) for big systems consisting of several hundred components.
2. Half rack (around 22U) for mid-sized organisms.
3. Quarter rack (up to 14U, commonly 11U) for small network systems and desktop installation.
If you need a compact rack for wall-mount or desktop installation, 6U or 9U server racks are the best choice. 6U and 9U are 10,5 and 15.75 inches high, respectively. 12U (with a height of 21 inches) is perfect for mid-sized systems. 18U or 22U are the most popular examples of small floor-standing models. They are 31,5 and 38.5 inches high. If you have a large network system that comprises hundreds of components, 37U or 42U are the best choice. The heights of these models reach 64,75 and 73.5 inches.
Each type of rack is designed for different purposes. Learn more about U rack dimensions in Sysracks’ blog. Sysracks is a trusted quality supplier of server racks and cabinets for network systems. Managers help pick a suitable option for clients’ demands.
How to Evaluate the Needed Amount of Us?
Once we figured out what the U means in server racks, it’s no less important to understand how to design the server rack and assess the correct amount of needed Us. Thus, to evaluate how many Us you need to accommodate your server systems, you need to consider the next parameters:
- Count the number of servers you have. One server usually takes the height of 1U.
- Make a list of other pieces of hardware that are 1.75 inches tall.
- Check whether your system has components that are taller than 1.75 inches. They will require 2 Us for accommodation.
- Count devices that take less than 1.75 inches and think about their ergonomic allocation.
The use of a proper rack model allows for maximizing space utilization in a data center. To simplify the task of proper space utilization, it’s recommended to make a 3D visualization, where system administrators can make an effective ergonomic layout for the rack. By allocating all devices in a digital cabinet, you minimize the risk of making a mistake and achieve high data center space optimization. When the layout is done, it’s each one to calculate the rack height in Us.
Additional Issues for U Consideration
When you consider server rack U meaning, the following aspects also matter. They affect the final choice of the rack U size:
- Security. Renting a certain amount of Us usually implies sharing space with other renters, which means poor security. Choosing a more spacious rack and putting it in a cage allows for improving security.
- Power draw. The rack size affects the amount of power it can draw. Sometimes, system administrators buy a bigger rack to satisfy the power demand of the system.
- Maintenance. Selecting the right rack size simplifies access to devices and speeds up maintenance.
- Expansion. In most cases, telecom systems tend to grow over time since more components are added to improve processing capacity and storage space. Thus, it’s advisable to buy bigger models and leave free space for future improvements. This step allows for achieving IT infrastructure efficiency since there is no need to re-buy new cabinets.
Understanding rack unit sizes for server deployment is a key skill for system administrators. Now, you know the explanation of the question “What is 1u rack space?”. We hope this information helps simplify the process of selecting an appropriate model and eliminating the risk of buying small or no-fitting server furniture.
