Choosing the right server rack is an important decision when setting up or upgrading an IT environment. A rack needs to do more than simply hold servers. It must provide enough space for equipment, support the required weight, allow effective airflow, accommodate cabling and power distribution, and leave room for future expansion.
Whether you are setting up a small business server room, network cabinet, data centre, or expanding an existing IT infrastructure, understanding rack size, dimensions, mounting requirements and cooling can help you avoid an expensive replacement later.
This server racks buying guide explains the key factors to consider before purchasing a rack in Australia.
What Is a Server Rack?
A server rack is a frame or enclosed cabinet designed to organise and secure rack-mounted IT equipment. Depending on the installation, it can house servers, switches, routers, patch panels, storage equipment, UPS systems and Power Distribution Units (PDUs).
Most rack-mounted equipment uses a standard 19-inch mounting width, while the available height and depth can vary significantly between rack models.
The right rack therefore depends on the equipment you plan to install, the available room, power requirements, cooling needs and expected future growth.
1. Determine How Much Rack Space You Need
One of the first things to consider when buying a server rack is rack unit (U) capacity.
A rack unit, commonly written as U or RU, measures vertical mounting space. One rack unit is 44.45 mm high. For example, a 1U server requires one rack unit, while a 2U server requires two.
Before choosing a rack, make a list of all equipment you currently need to install, including:
- Rack servers
- Network switches
- Routers
- Patch panels
- Storage equipment
- UPS systems
- PDUs
- Cable management accessories
Add the U height of each item to calculate your current requirement. However, do not select a rack that is only large enough for today’s equipment.
Allow additional rack space for future expansion. If your equipment currently requires around 20U, for example, choosing a larger cabinet can provide valuable room for additional servers, networking equipment or power management hardware later.
2. Choose the Correct Rack Depth
Rack height is only one part of the sizing equation. Depth is equally important, particularly when installing modern servers and storage equipment.
A rack that is too shallow may prevent equipment from being installed correctly or leave insufficient space for rear cabling and airflow. Server rack depths can vary considerably, with deeper cabinets generally being better suited to larger servers and more complex installations.
Before buying, measure the deepest piece of equipment you intend to install and consider:
- Equipment depth
- Rail requirements
- Power cable connections
- Network cabling
- Cable management arms
- Rear airflow
- Clearance between equipment and the rear door
Remember that the external rack depth and usable internal mounting depth are not necessarily the same.
3. Consider Rack Width
Most standard rack-mounted equipment is designed around a 19-inch mounting width. However, the overall external width of a cabinet can be greater to provide additional space for cable management and airflow.
A wider cabinet can be useful when you have extensive cabling or need additional side-management space.
When measuring your installation area, check the complete external dimensions rather than assuming that a 19-inch mounting width means the cabinet itself will be only 19 inches wide.
4. Decide Between an Open-Frame Rack and Enclosed Cabinet
The environment where the rack will be installed should influence your choice.
Open-Frame Racks
Open-frame racks provide easy access to equipment and can offer excellent airflow. They may be suitable for controlled network rooms where physical security and dust protection are less of a concern.
Enclosed Server Rack Cabinets
Enclosed cabinets provide additional physical protection and can help create a more organised and secure installation. They are particularly useful when equipment needs protection from accidental contact, dust or unauthorised access.
For offices, server rooms and environments where equipment security is important, an enclosed cabinet may be the more practical option.
5. Check Weight Capacity
IT equipment can become surprisingly heavy once a rack is fully populated.
Before purchasing a server rack, calculate the approximate weight of your servers, storage systems, UPS equipment and other rack-mounted hardware. Then check the manufacturer’s specified load capacity.
Do not select a rack solely on its physical dimensions. The cabinet must be capable of safely supporting the equipment you intend to install.
For larger installations, also consider the floor loading capacity and whether the rack will need to be moved after installation.
6. Plan for Cooling and Airflow
Effective cooling is essential for maintaining reliable IT equipment.
Servers, storage devices, switches and UPS systems generate heat. If hot air cannot escape effectively, temperatures inside the rack can increase and affect equipment performance and reliability.
When evaluating a server rack, consider:
- Perforated front and rear doors
- Ventilation openings
- Rack-mounted fan options
- Equipment airflow direction
- Clearance around the cabinet
- Room-level cooling
- Hot-aisle and cold-aisle arrangements in larger installations
A well-planned rack should support the airflow pattern of the equipment installed inside it rather than obstructing it.
7. Think About Cable Management
Poor cable management can make an otherwise professional server rack difficult to maintain.
Before selecting your rack, consider where power and network cables will enter and exit the cabinet. Look for suitable provisions for vertical and horizontal cable management.
Good cable organisation can make it easier to:
- Identify connections
- Troubleshoot problems
- Replace equipment
- Maintain airflow
- Add new devices
- Reduce cable clutter
A rack should therefore be planned as part of the overall IT infrastructure rather than purchased as an isolated piece of equipment.
8. Consider Power Requirements
Your rack also needs an effective power strategy.
For critical infrastructure, you may need a UPS (Uninterruptible Power Supply) to provide backup power during interruptions and a PDU (Power Distribution Unit) to distribute power to rack-mounted equipment.
When selecting your rack, make sure there is sufficient space and suitable mounting options for your power equipment.
This is particularly important when the rack will house servers, networking equipment or other business-critical hardware.
9. Think About Future Expansion
A common mistake is choosing a rack based only on current requirements.
IT infrastructure changes quickly. Your business may add servers, switches, storage, security equipment or additional power protection over time.
Instead of selecting a rack that is completely full from day one, allow some capacity for future expansion. This can reduce the need to replace the cabinet when your infrastructure grows.
A slightly larger rack can sometimes be a more cost-effective long-term choice than purchasing a small cabinet and replacing it later.
Choose the Right Server Rack for Your IT Infrastructure
The best server rack is not necessarily the largest or most expensive option. It is the one that matches your equipment dimensions, rack-unit requirements, weight, cooling, cable management, security and future expansion plans.
For Australian businesses, taking the time to assess these factors before purchasing can help create a more organised, serviceable and scalable IT environment. Source 22 provides a range of server rack solutions designed to support different IT infrastructure requirements. Explore the Server Racks range to find a suitable solution for your setup.
Frequently Asked Questions
- What size server rack do I need?
The required size depends on the total rack units of your equipment, equipment depth, cabling requirements and future expansion. Calculate your current U requirement and allow additional capacity for growth. - What is 1U in a server rack?
1U represents 44.45 mm of vertical rack mounting space. Rack-mounted equipment is commonly specified by its U height. - How deep should a server rack be?
The required depth depends on your deepest equipment and the additional clearance needed for rails, cables and airflow. Always check the equipment manufacturer’s installation requirements before choosing the cabinet depth. - Should I choose an open-frame rack or enclosed cabinet?
Open-frame racks provide accessibility and airflow, while enclosed cabinets provide additional physical protection and security. Your installation environment and equipment requirements should determine the best option.
