19” cabinets and racks have been around for years but the demands of technology in the last decade have forced a revolution in their design. What was once a relatively simply designed steel construction is now a more 
sophisticated structure that performs an integral role in the functioning of a data centre.
The exponential increase in data transmission, via the internet, online services, video, telephony, mobiles and tablets have increased the need for data storage, bandwidth and processing capability. The growth in data centres and the need for increasingly higher density racks and cabinets have forced manufacturers to review their product designs.
Key issues that need to be addressed in today’s cabinet design are: power/heat dissipation, security, monitoring and equipment housing.
Power/heat dissipation
Higher density servers means more servers per cabinet and this impacts on the heat generated from within each cabinet. A simple cabinet today can generate triple the amount of power compared with ten years ago; a high end server cabinet can generate twenty to thirty times more power and the proportionate heat to go with it. This dramatic increase in heat has rendered cooling one of the critical issues in both cabinet and data centre design.
For an individual cabinet, heat is typically extracted by front to back airflow through mesh doors. Computer room air cooling units (CRAC) feed cool air into the cold aisle and then out in to the hot aisle. From there, heat travels back to the CRAC units for further cooling. In extreme cases, fans may need to be added to rear doors to pull hot air through the unit more quickly.
Within an individual cabinet, it is essential to control airflow so that back-to-front (hot side to cool side) is eliminated. It is also important to install cabinets where the cooling can be upgraded over a data centre’s lifetime.
Security
Security is obviously an issue where a cabinet is located in a hosted data centre, but is not confined to co-location environments. Traditionally simple security features such as passive key operated locks or even code operated ones were considered sufficient. Now more sophisticated technologies are used such as software controlled code, iris or thumbprint recognition, with in-built alerts if there is a security breach. All of these technologies need to work at cabinet level and can be linked to CCTV and video systems for local or remote monitoring. In some cases cabinets can be configured for 2 person authentication, meaning that two specified personnel must be present before the cabinet will unlock. Again security systems are advancing all the time and it is important that users select cabinets that can accommodate security upgrades over their lifetime.
Monitoring
As the data centre environment becomes more complex and higher in density – there is more to monitor at both the data centre and cabinet level. Most of the devices installed in a data centre environment will provide information to the Network Manager as to their functionality. This level of “Intelligence” has now moved down to cabinet level with the development of Intelligent PDU’s that can be managed locally or remotely at socket level to ensure that power and heat levels are being optimised and managed efficiently. These PDU’s are located within the cabinets and can be vertically or horizontally mounted.
Equipment housing
Whilst there is a standard measurement system in place such that all vendors’ equipment will neatly fit onto a 19 inch cabinet, the reality is not always that straightforward. In some cases equipment won’t fit. It is important to deploy cabinets that are designed with in-built “adjustability” to accommodate devices with more quirky dimensions. It’s also important that cabinets can retain the highest levels of back-to-front airflow isolation even when they are housing lots of different sizes and shapes of equipment.
Modularity
By nature of their shape, cabinets have always been fairly modular in design, but never before has this modularity been so important. Firstly when selecting a cabinet for purchase from a quality vendor, it is possible for customers to “build” their cabinet by selecting the necessary component elements for their specific requirement. Post installation, cabinets that are fully modular in design can be altered to cater for a change of their use or to incorporate upgrades over time.
The small business user
Not all cabinets are used in a data centre environment, but the good news for the smaller business user is that the demands of the data centre environment have accelerated the design and variety of cabinets available on the marketplace, such that many of the features are included in free-standing cabinets used in the business environment. This has also positively impacted on the cost of cabinets available today.
So, there are a number of factors to consider when purchasing a cabinet. You need to ensure that you can adequately address the power, heat, security and access issues. You also need to be confident that the cabinet can be upgraded extending its life beyond the current application. Experience shows that well established and reputable cabinet and rack manufacturers are developing their products on a continual basis and that it pays to invest in a good quality cabinet that will last.
