Server Racks by Type

Server racks are essential equipment in data centers, server rooms, offices, and even home labs. They provide organized, secure, and efficient mounting for servers, networking gear (like switches and routers), storage devices, UPS units, and cabling. To ensure broad compatibility across equipment and rack manufacturers, server racks are built to the Electronic Industries Alliance (EIA) ANSI/ EIA/ECA-310-E standard, based on the work of the Electronic Components Industry Association (ECIA) EIA Standards Committee and "developed in accordance with, and accredited by, the American National Standards Institute (ANSI)" (https://www.ecianow.org/eia-technical-standards)

Though overall width and depth can vary significantly, the EIA standard mounting width for server racks is 19 inches (482.6 mm), with height measured in rack units (RMU or simply U) - where 1U equals 1.75 inches (44.45 mm). Racks typically range from small 4U wall units to full-height 42U, 48U, or even 52U floor-standing models.

Less common than standard 19" racks, another standard mounting width is 23". This mounting width is found mainly in the telecom industry and is not as widely available as the 19" standard-width rack.

Server Rack Types

Server racks vary widely based on design, mounting style, enclosure level, and intended environment. Several types of server racks fall into four broad categories. Here's a breakdown of the main types commonly used today. 

Open-Frame Racks - These are the most basic and cost-effective options, consisting of vertical posts (rails) without side panels, front/back doors, or full enclosures. Subtypes include:

• 2-Post Racks: (also called telco or relay racks): Feature two vertical posts; ideal for lighter equipment such as patch panels, switches, or telecom gear. They require less depth and floor space but support lower-weight loads.
• 4-Post Racks: Have four vertical posts for better stability and support heavier servers or storage arrays.
• Cable Management Rack: Some open-frame racks come with integrated cable management for high-density and structured cabling applications.
• Conversion Kits: Many 2-post racks can be combined with a 2-post conversion kit to create a 4-post rack or securely anchor the 2-post rack to a wall.

• Advantages: Excellent airflow (great for passive cooling), easy access from all sides, simple cable management, and lower cost.
• Disadvantages: Minimal physical security (no locking), dust exposure, and less protection from accidental bumps.
• Best for: Network closets, wiring rooms, environments where security isn't critical, high-density cabling setups, and environments where cooling is not a concern.
• Typical sizes: 24U–52U height, various depths.

Enclosed Cabinet Racks (Rack Enclosures) - Also known as server cabinets or floor-standing enclosures, these are fully or partially enclosed units with front and rear doors (often perforated for airflow), lockable side panels, and, in some cases, removable panels.

• Key features: Locking mechanisms for security, integrated cable management channels, adjustable mounting rails, and often built-in provisions for power distribution units (PDUs), fans, or cooling accessories.
• Advantages: High physical security, better dust/noise control, organized appearance, and protection for valuable equipment. Many support active cooling setups.
• Disadvantages: Higher cost, reduced natural airflow (may require fans or perforated doors), and heavier overall.
• Best for: Data centers, enterprise server rooms, colocation facilities, or any location needing security and professional organization.
• Typical sizes: 24U–55U (most common is 42U), with depths from shallow (~24–32 inches) to deep (~42–54 inches) for modern high-density servers and AI applications.  While mounting width is fixed, overall cabinet widths can range from 23 inches to 32 inches or more for some ultra-wide cabinets.

Wall-Mount Racks - These attach directly to a wall, saving floor space.

• Variations: Can be open-frame or enclosed (small cabinet style) and fixed or Swing-out racks.
• Advantages: Compact, ideal for tight spaces - including corner mounting cabinets, keeps equipment off the floor, and relatively inexpensive.
• Disadvantages: Limited capacity and weight support; not suitable for heavy or deep servers.
• Best for: Small offices, branch locations, home labs, retail setups, classrooms, or remote sites with minimal equipment (e.g., switches, firewalls, small servers).
• Typical sizes: 4U–22U.

Other Specialized Types

• Portable / Rolling Racks: Open or enclosed designs on wheels/casters for mobility. Useful for testing labs, temporary setups, or moving equipment between locations.
• Low-Profile / Desktop Racks: Small units (often 1U–12U) that sit on desks or shelves for non-data-center use.
• Industrial-Grade Racks: Built for harsh environments (factories, outdoor, hazardous areas) with enhanced durability, sealing, or shock resistance, including NEMA 12 Enclosures and Seismic Racks.
• Colocation Racks: Modular enclosed units designed for shared data center spaces, often with partial/full-rack rentals and strong security features.

Quick Server Rack Comparison Table

Key Considerations When Choosing a Server Rack

• Space & Location - Floor-standing for data centers; wall-mount for limited areas. Don't forget to make sure the rack will fit in the doors of your space. Tall racks and wide racks can pose an issue moving through standard doors.
• Security Needs - Enclosed/lockable for sensitive data.
• Cooling Requirements - Open frames for natural airflow; enclosed with perforated doors or fans for denser setups.
• Weight & Load - Check rack weight capacity (especially for 2-post vs. 4-post) static loads for racks that do not move and dynamic loads for racks that will move.
• Depth - Modern servers often need 36–48 inches; older gear may fit shallower racks.
• Future Scalability - Opt for adjustable rails and room for growth.

Server racks continue to evolve with trends such as liquid-cooling integration and higher densities (especially for AI workloads), but the core types above remain the foundation for most deployments. Selecting the right one depends on balancing budget, space, security, and equipment needs.  If you have any questions on what rack will work best for your envirohnment, speak to one of our server rack experts today!

Be it a full enclosure, open frame, or wall-mount rack, no matter the type of rack you are looking for, you can be sure to find it at Server Racks Online, your Server Rack Super Store!