Ranking your selection criteria when choosing the best IT rack for your data centre

JOHANNESBURG – October 12, 2015 – With so much to think about, ranking your selection criteria when choosing the best IT rack for your data centre is imperative. Before a rack is selected, some decision criteria should be considered, such as dimensions, operational design, structural design, material, and colour; along side the actual components your rack will house.

Based on the IT rack components and decision criteria mentioned above, and according to a Schneider Electric whitepaper, entitled How to Choose an IT Rack, the following rack selection process is recommended:

  • Identify the attributes of IT and non-IT equipment to be mounted;

  • Select IT rack dimensions and load capacity based on the attributes of equipment;

  • Select IT rack preferences; and

  • Select IT rack accessories for power, airflow, cabling management, and monitoring. Identify the attributes of IT and non-IT equipment to be mounted;

Identify the attributes of equipment to be mounted

Depending on the equipment mounted inside the IT rack, it would be categorised as either a server- or a network rack.  Network racks are usually wider than server racks due to extra space required for cabling.  Therefore identifying the attributes of the IT equipment will help establish some basic rack parameters, such as dimensions and load capacity.  The attributes of non-IT equipment should be considered as well, such as rack power distribution unit (PDU), automatic transfer switch (ATS), rack-mounted uninterruptible power supply (UPS), and so on

The following key attributes affect the choice of rack:

  • Number of power cords (affects cable management in the rack);

  • Cooling requirements, including side-to-side or front-to-rear airflow, CFM, and so on;

  • Rack unit (RU) spaces to be occupied;

  • Width and depth dimensions of IT and non-IT equipment;

  • Total IT and non-IT equipment weight; and

  • Network ports required – how many cables are entering the rack.

Based on the attributes of IT and non-IT equipment, the minimum requirement for the IT rack width and depth dimensions and load capacity can be determined.  However, three factors should be considered before selecting IT rack dimensions and load capacity.

The first is the growth plan of the IT equipment.  An IT rack generally has more than an eight-year life cycle, which will support multiple generations of IT equipment.  Most IT equipment is standardised for mounting into a 19-inch rack.  If the data centre will use standard homogeneous IT equipment, oversizing the rack may not be required.  However, if future equipment needs are unknown, oversizing the width and depth may be the right approach.  In some cases, administrators or data centre designers want to maximise the number of racks in their data centre but also want racks with extra room for cabling.  In these cases, multiple rack layouts (horizontal and vertical directions) are created to compare the rack quantities between wide racks and deep racks.

The second factor is the rack density (kW/rack).  Higher rack densities generally translate into higher rack weight.  Ensure that the rack is capable of supporting the weight load at the maximum rack density.

Finally, IT rack vendors typically offer standard IT rack models based on market analysis.  Selecting from standard rack models is generally lower cost compared to non-standard racks.  Standard, vendor-neutral racks almost always guarantee universal compatibility and allow for greater flexibility when purchasing and mounting equipment

Select IT rack preferences

Some preferences include colour, door style (curved, angled), type of door lock, and seismic bracing amongst other features.  Regardless of preferences chosen, design criteria should be maintained; for example, any change to the front or rear door should not restrict the required IT airflow.

Select IT rack accessories

Selecting an IT rack is obviously critical to data centre availability; however selecting rack accessories improves operational efficiency. Accessories play an important role in IT racks, with suppliers providing more accessories for specific applications.  Note that, depending on specific requirements, some rack components may not be required and are purposely excluded from an IT rack solution.  For example, rear doors are commonly excluded for racks used in a hot aisle containment system.  In some specific applications, IT racks must be anchored to the floor for stabilisation, therefore ensure castors and levelling feet can be removed.

“Only if IT racks and their attributes are well known before the installation, can the right rack solution be recommended, evaluated and managed, bearing in mind the future growth plan, rack performance and user preference requirements. Still racking your brain with where to start? Contact us for help, guidance, and the right solution for your business,” adds Bruce Grobler, southern Africa director of the IT business unit at Schneider Electric.

About Schneider Electric

Schneider Electric is the global specialist in energy management and automation. With revenues of €25 billion in FY2014, our 170,000 employees serve customers in over 100 countries, helping them to manage their energy and process in ways that are safe, reliable, efficient and sustainable. From the simplest of switches to complex operational systems, our technology, software and services improve the way our customers manage and automate their operations. Our connected technologies will reshape industries, transform cities and enrich lives. At Schneider Electric, we call this Life Is On.



Schneider Electric, Isabel Mwale, +27 (0) 11 254 6400, isabel.mwale@schneider-electric.com

PR Connections, Debbie Sielemann, +27 (0) 82 414 4633, schneider@pr.co.za

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