A Guide to Buying Server Racks and Data Cabinets

Server racks and data cabinets have become the go-to solution for housing servers, storage devices, network routers, patch panels and a host of other associated devices including uninterruptible power supplies, power distribution units and environmental monitoring systems. The choice can seem daunting but it is a relatively easy process to size, select and buy the right rack or cabinet for your installation online. This guide covers some of the general areas to consider.

What is a Server Rack?

A server rack is a standardised framework designed to hold one or more IT servers, storage, networking devices and audio visual (AV) equipment in a vertical format. Server racks (also known as server cabinets or data cabinets) typically have a series of slots or ‘rack units’ measured in 1U increments, where 1U equals 1.75inches / 44.45mm in height. The front and rear vertical pillars or supports in a rack will show the U height increments from 1 to the overall height of which can be up to 47U or higher.

This standardised height arrangement makes it easy to calculate how much equipment a rack can take or alternatively how much U height is required. Equipment designed for server racks, including UPS systems will show a height dimension in mm and U. This makes it easier to identify the right sized U-height cabinet but there are other considerations to make.
Server racks predominantly used in server rooms and data centres, but the concept is also found in other areas and cabinets. Wall mounted cabinets and outdoor cabinet enclosures for IT devices will use the ‘server rack’ concept. As will Edge systems including micro data centres.

In addition to providing a convenient way to scale vertically and house suitable 19inch rackmount equipment, server racks also play a critical role in managing airflow, cooling arrangements, environmental monitoring, fire suppression and power protection.

What is a Data Cabinet?

A data cabinet is very similar to a server rack but tends to be smaller in size and wall mounted. Data cabinets are used for smaller IT network items, housing them aware from the main server room or data centre, in areas that require additional connectivity or coverage (e.g. WiFi routers).

Server Rack Dimensions to Consider

1. How do I choose the right Server Rack or Cabinet Enclosure The starting point is always an equipment list and preferably in Google Worksheet or Microsoft Excel format. This could be taken from your asset register and typical table headings could include: Item Number, Equipment Description, Rackmount (Y/N), Height (U), Depth (mm), Power Required (Watts and Socket Type. In this example, the table lists the server first, that it is rack mount, 1U high, 560mm deep, requires 300W of power and requires an IEC C14 plug. For equipment to go into the rack that is not available in 19inch rackmount format, a shelf may be needed. Typical shelves include fixed length, adjustable and telescopic. Once the list is complete, the total required U height required can be calculated and a suitable server rack chosen. This could include additional U-height for future expansion or for air flow between devices. For example, if there is a rack mount UPS (which would normally go at the bottom of a rack), several U height space may be left above this for air flow. Other devices for the list could include a rack mount environmental monitoring device.
2. Usable Internal Depth The depth of the devices to be housed is important. Whilst server racks have typical depths of 600mm, 800mm, 1000mm or 1200mm this measurement is the total overall size from front to back, including the doors. The maximum actual usable depth between the vertical supports (which are usually movable) will be less. For example, a typical 800mm rack have only 670mm of usable space. When selecting a suitable cabinet depth, remember to add say 50mm to the depth of the devices to be housed to cover power cord arrangements.
3. Usable Internal Width Most cabinets are 600mm wide. This is the outer dimension of the cabinet including side panels. Inside a 600mm wide cabinet, the vertical struts or pillars will be spaced to house the 19inch (483mm) wide equipment. If additional space is required between the pillars and the side panels for cabling, then an 800mm wide cabinet is the next size generally available.
4. Maximum External Server Cabinet Dimensions the dimensions for a rack may be shown as 27U x 600W x 1000D. As mentioned, 27U is the internal usable height. The overall height of the rack should be shown on a webpage or datasheet and could, for example be 1458Hmm. If you took 1458m and divided by 44.45mm (1U) this would appear to be a 32U high cabinet which it is not! For this specific cabinet the overall height is from the floor to the top of the cabinet including 70mm for standard castors. Heavy duty castors may may add another 30mm as they could add 100mm overall to the height of a cabinet. Why are the overall dimensions important? Logistics and space on site. It is important if your cabinet is delivered assembled that it can easily be moved front the front of the building to the final point of use. This means making sure the cabinet can be taken through door frames (consider width and height of the frames and the overall cabinet dimensions). If the final point of use is not ground floor, then lifts and stairs may have to be considered. If there are too many obstacles, then perhaps a flatpack is needed with build onsite. For the final position also consider ceiling height clearances, access to the cabinet (front, sides and rear; side panels can be removable for easy access) and overall position in the room. If a flat pack is ordered, then there should be a suitable working space for assembly of the cabinet.

For more information see our guide on server rack and cabinet sizing.

Server Rack Doors and Security Arrangements

Most server racks are available with a choice of doors. These can include bronze glass, steel, perforated and mesh. Doors can be single or wardrobe type doors (split in the middle). The choice of door format is very much dependent upon the aesthetics, cooling and security required. Most doors will have a keylock handle. Alternatives can include combination lock handles or handles with an RFID reader for connection to the local access control system.

Server Cabinet Types

Most suppliers and manufacturers will offer a range of cabinets. These can include:

• Floor standing or Wall mounted: generally available from 4U to 47U, floor standing cabinets are the most commonly used in computer rooms, server rooms and data centres. Wall mounted cabinets or data cabinets as they are sometimes referred to are commonly used for small networking devices. For example, in a warehouse or retail store, the back office may have a server rack, with wall mounted data cabinets in the goods-in areas and on the shop floor to house WiFi and routers. Some manufacturers of racks in budget or premium types. The difference lies in the thickness of steel used to finish the cabinets and the typical weight loadings they can support.
• Industrial Cabinets: this type of cabinet is for industrial, factory, process manufacturing and other areas where the air quality is less controlled than in a server room or data centre, and a more robust design is required with a higher IP rating (IP54) with fan/dust filters. A higher IP rating may also protect from water ingress The cabinet protects the standard IT servers and networking devices in these extreme and harsher environments.
• Air Conditioned Cabinets: these cabinets have a side mounted air conditioner (1.5 to 2.5kW of cooling) to provide a temperature / humidity controlled internal space for the servers and IT devices of around 20-25°C. This type of cooled cabinet is ideal for areas where there is no room cooling or air conditioning. Generally, rack manufacturers will offer a limited range of 27U and 42U high cabinets, 800 or 100mm deep.
• Acoustic or Soundproof Racks: these cabinets have additional soundproofing lining and super silent cooling fans that can help to reduce typical noise levels by 95% and may be more suitable for server racks placed in an office area rather than a computer or server room.
• Outdoor or Weatherproof Cabinets: used to house IT equipment in outdoor areas. This can include Edge facilities and point of entry to site fibre cable and associated IT networking routers.
• Open Frames: as the name suggests, this type of rack has no doors or sides and is a frame. Typical uses for an open-frame arrangement is for telecoms to mount equipment and patch panels, allowing easy access for cable management, home offices for servers, NAS devise and networking gear where it can assist with cooing, laboratories to hold test equipment, Audio Visual applications for mixers, processors and studio equipment.

For more information see our server rack range including UK manufactured server racks and server cabinets from data centre brand leaders including APC (Easy Rack and Netshelter Cabinet ranges), Eaton, Prism, Tripp Lite and Vertiv amongst others.

Server Cabinet Accessories

When you have selected the right server rack(s) for your installation, there are other items that you may want to consider. These will add to the functionality and efficiency of use of the space and thermal management within the rack.

We’ve listed the different cabinet accessories below, which can be used with a data cabinet. Each accessory has been given a brief introduction so you can familiarise yourself with the product before making any decisions on whether you need them for your server room setup. The accessories include:

• Blanking Panels: available from 1U upwards in size, blanking panels are a useful addition to any server rack. They attach to the vertical struts and infill the front space for unpopulated areas of a rack. The panels help improve front to rear airflow, support a cold/hold aisle configuration and prevent rear exhaust warm air from servers mixing with the incoming cool air at the front of the cabinet. They can be solid infill or vented panel and also be supplied with brush strips for cable entry.
• In-rack Cooling: in the form of root top fans or fan shelves to help with upwards airflow within the cabinet, drawing the warm air up and helping to exhaust.
• Cable Management Rings and Bars: cable rings and cable bars to help tidy-up and manage cabling within the rack. Typically, available as 40×40 or 70×70, 1U sizes.
• Shelving: a range including fixed size, adjustable and telescopic and small modem shelves. A shelf is ideal for any item that needs to go into the rack that is not 19inch rack mountable. Devices ideal to go onto a shelf include a modem or WiFi router, tower UPS or small environmental monitoring device.
• Patch Panels: to help manage overall cable management. These units are rack mounted and have a quantity of RJ45 ports. Ideally there should be a cable port map with each cable uniquely identified for its location and usage.
• Basic or Smart PDUs: ideal for helping to manage power cords suppling power to the different devices. The PDU can be horizontal or vertical in format and should have suitable socket types (IEC C13, UK BS1363 square pin) to meet the connection types required. The rack equipment map mentioned previously should list the outlet types and quantity required.
• Uninterruptible Power Supply: a UPS system will be an important feature of any server rack that has to keep running during a short or prolonged power outage. The UPS is typically rack mounted (up to say 3kVA) with a matching battery tray for extended runtimes. The device is normally placed at the bottom of the rack due to its weight (affecting the centre of gravity of the rack) and to keep the battery set at the coolest part of the rack (the bottom, note warm air rises and cold air falls). For larger runtimes or UPS (up to 10kVA) the battery packs may be external. A bypass arrangement for maintenance is generally advisable as the UPS can then be maintained without disruption to the load. The bypass may be wall mounted or 19inch rackmount.
• Environmental Monitoring Device: small but sometimes overlooked device for any server rack is an environment monitoring unit. A range of compatible plug in sensors can be used to monitor for temperature, humidity and water leakage and issue notification alerts via Email and if required SMS text messages and phone calls. Reporting via SNMP is also a typical feature. Suitable notification of alarm events allows action to be taken which can ensure overall business continuity. For example, a high temperature can indicate failure of the local air conditioning which can have catastrophic effects as the temperature within the rack rises if unchecked, leading to a potential fire hazard.

For more information see our server rack accessories range.

Buying Server Racks Summary

It is important to start with a defined list of the equipment to be mounted in a 19inch server rack or cabinet. This helps determine the overall U-height required. Width and depth of rack can then be determined based on the overall depth of the items to be installed and the need for side access and cable management ease. The overall size of the cabinet also has to be deliverable and for this it is necessary to check the route and final position of the rack to ensure a clear path and ease of delivery. The overall usefulness and ability to support operations of the chosen server rack can be increased through a range of accessories including cooling, power protection and environmental monitoring.

Buying a server rack is relatively straight forward and at Server Room Environments we provide a hotline (UK +44-(0)800 030 6838 ) for prospective clients and existing customers to call should they need additional advice and support. A member of our projects team is always on hand to ensure you get the right server rack for your application. In addition to our general kirbside delivery service, we also provide project specific delivery, siting and positioning services to get your rack cabinet to where you need it exactly within your building. This service can be used for either fully assembled cabinets and flatpack kits. We also provide onsite build and fitout teams as required.

For new projects and enquiries please contact us (phone or email) or complete our online enquiry form. You can also use this form to upload additional information for your rack or cabinet project including photos, site informtion and drawings for our projects team to review.