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Rack Server - a Closer Look

What Is a Rack Server?

Rack servers are mountable servers placed in metal frame racks. Rack servers are one of three form factors for servers, with the other two standards being blade servers and tower servers.

As data centers and IT professionals worked to develop improved methods for storing more servers while not sacrificing space or connectivity, server racks entered the scene. Server racks offer the space, fit, and proper environment for servers to continue operating at a high performance.

What is a 1U rack server?


Racks are designed to hold the dimensions of rack servers. Standardized frames are 19 inches wide and a variable number of rack units or U’s (equivalent to 1.75in) in height. A standard rack-mount server is a 1U rack server, with a width of 19″ and a height of 1.75″. Most rack servers are 1U or 2U, but the largest rack server comes in at 70U (10ft).

With pre-installed rails for a 2U rack server’s height, the data center administrator only needs a push inwards and rack screws to secure the 19″ by 3.5″ module into the rack.

Also Read: Dell Continues to Rise
Rack Server Components
Component     Function
Motherboard     Enables communication between components
Central Processing Unit (CPU)     Executes start instructions; also known as the processor
Random Access Memory (RAM)     Stores server memory; increases speed of data access
Host Bus Adapter (HBA)     Connects external devices to server
I/O Ports     Embedded into system board for endpoint access into system
Drive Bays     Open slots for adding hard drives (HDD) or solid state drives (SDD)
Supporting equipment     All else needed for smooth performance: rails, screws, cable managers, cooling system, sensors, etc.
NVMe     Non-Volatile Memory express facilitates access to storage and come in the form of SSDs, NVMe cards, and M.2 cards
PCIe     Peripheral Component Interconnect express connects expanded hardware to the motherboard

How Are Rack Servers Compared?

Manufacturers have designed servers to do just about everything you can imagine a computer to do. When comparing rack servers, the indicators frequently used to compare products include:

  • Target workloads: What tasks is the server capable of or specializes in doing?
  • Processor type: Which CPU processors are included with the rack server?
  • Memory: What is the server’s RAM capacity and DIMM slots count?
  • NVMe drives: How many drives of NVMe drives are available?
  • PCIe slots: How many PCIe slots are there and are they compatible with 3rd and 4th Gen PCIe?
  • Disk drives: What size and how many disk drives are insertable?
  • Storage: How much total storage is possible?
  • Rack height: How many Us does the device take up?
  • Operating systems: What OS software is the server compatible with?
  • Integrated security: What security features come pre-installed on the server?

How Do Rack Servers Work?

The rack environment has been critical to organizations because it offers interchangeability and access for essential components, including the server rack. A server rack’s easy implementation also means server administrators can easily remove them for inspection and troubleshooting. Rack servers can also hot-swap with another server to continue the mission-critical activity and limit downtime.

Because a rack server describes the form factor and not the intent, rack servers can take on any number of roles for a network. Responsibilities could include storage, email, web, proxy, application server duties, data-intensive applications, and more.

Benefits of Rack Servers
Self-contained and accessible


Rack servers are designed with their power source, CPU, and memory to run as a standalone or network system. The server’s operation is independent of the remaining rack components, which means that the rack server can be installed, configured, or removed quickly–without disassembly of the rack’s infrastructure or downtime.

Efficient space usage

In a world intent on expanding resources, available physical space is a data center’s most precious gift. The thinking goes more space, more racks, more server power. Racks and the servers built to fill them maximize space limitations with the dense organization. Unless dealing with a 70U rack server, frames hold many servers and equipment that save space.

Cooling mechanism

A top priority of any server administrator is ensuring the module won’t overheat when working hard. Unlike blade and tower servers, rack servers have an incredible capacity for a cooling system. Many racks come pre-installed with cooling systems today, with more available for installation. Fit with real-time sensors and accessible configuration, the rack server’s cooling mechanism protects against overheating and system failure. And the more powerful and densely packed servers become, the more important cooling becomes.

Rack Server Considerations

Though many of the top solutions share some of these features, buyers should consider the following factors when purchasing rack servers:

  • Processing Power
  • Scalability
  • Expandability
  • Upgradability
  • Size, Weight, and Power (SWaP)

Whether an organization needs additional storage, additional servers, or a server replacement, rack servers are the best form factor. With their portability and ease of access, organizations can scale, expand, and upgrade their systems seamlessly. Still, processing power remains the biggest selling point for server manufacturers.

Size, weight, and power (SWaP) also play their part and can cause faulty server or rack performance if not correctly configured. For example, an overly heavy rack server could require more cooling. Without adjusting the cooling system or moving other components, the rack’s pieces are at risk of overheating.

Server Market

After raking in $83.66 billion in 2020, the global server market is expected to grow at a CAGR of 7.8%% between 2021 to 2028. Rack server sales accounted for over half of server market revenue with $43 billion.

As noted, nearly 50% of the server industry market has long been owned by Dell, HPE, and IBM. One of the reasons for this is clear market stratification—the ODM white boxes on the low end and the midrange and high-end systems are experiencing massive growth as separate segments. So as you shop, be aware of what price level you find most appropriate for your business.

More than just high-computing machines, vendors continue to add features that support big data analytics, software-defined solutions, and hyper-converged infrastructure. Factors influencing the server market include increasing data center needs and the adoption of new technologies like cloud computing.

Rack Servers: Contained, Condensed, and Cool

Rack servers are self-contained to prevent disruption to other rack components, condensed to offer high-powered performance in minimal space, and are kept cool to facilitate the best environment for work. On top of these features, rack servers offer organizations scalability, expandability, and upgradability. Racks offer both the additional space and structural framework for organizations to scale out or up and upgrade when necessary.