In data centers, the size or height of racks are usually measured in units. A decade ago, 36-units were the standard rack size, which has now grown to 42-units in more than 60% of the market according to Faisal Ghaus, the VP of analyst firm TechNavio. The industry standard today is a server rack of 7 feet, which, in a 19 inch wide slot, can accommodate 42-units of rack mount server equipment. However, the rack sizes have doubled in the last 10 years and the industry now has sizes ranging from 44-units to 58-units (nine-foot to 11-foot tall racks).

Predictions for Rack Unit Growth in Data CentersThe IMS Research reveals that the 48-unit racks shipment will show a 15% annual growth in 5 years, while the 42-unit rack demand will grow only 5%. 48- and 51-unit rack sizes together contribute to 10% of the market today and are expected to cross 20%, says Ghaus. The demand for increasing rack sizes is the result of companies looking for better utilization of current data center space, which is far cheaper than constructing new facilities or expanding existing facilities to incorporate their ever-growing IT resources.

Though taller, non-standard racks accommodating more servers is a viable solution to growing customer demands, it doesn’t come without drawbacks. Does it affect the cooling and airflow management in data centers? Let’s see:

  • IMS research indicates that the size may be regulated to 45-unit and 48-unit racks, given the logistical limitations associated with racks of 51/52 units or higher. Truck height restrictions and doorway opening space restrictions would also be factors to consider for transporting racks above this height.
  • Even if shipping challenges are bypassed, there are still other factors to consider within the data centers. Not allowing enough sprinkler clearance space while deploying taller racks can lead to code violations.
  • Another concern with increasing servers in cabinets is rack weight increases will sometimes exceed the raised floor load capacity, which can, in turn, collapse the floor.
  • Taller racks means more servers, which can lead to more cables, making management difficult and can demand wider and deeper cabinets to accommodate those. Cables should be managed properly (tight and straight), leaving enough room for the exhaust air to exit from the cabinet.
  • Increasing the rack height can require changes in the rest of the rows, creating problems for installing containment systems. More servers in enlarged cabinets demand more conditioned air, which is often not met in most computer rooms. Before adding additional IT equipment, increase the volume of conditioned air delivered to the aisle by directing conditioned air to areas needed. This can be done through proper management of open areas in raised floor.

When installing taller racks, don’t overlook these challenges, and never make a decision without getting all of the information you need. Talk to our experts to find out what is good for your data center.

Rich Banta

Rich Banta

Managing Member at Lifeline Data Centers
Rich is responsible for Compliance and Certifications, Data Center Operations, Information Technology, and Client Concierge Services. Rich has an extensive background in server and network management, large scale wide-area networks, storage, business continuity, and monitoring. Rich is a former CTO of a major health care system. Rich is hands-on every day in the data centers. He also holds many certifications, including: CISA – Certified Information Systems Auditor CRISC – Certified in Risk & Information Systems Management CDCE – Certified Data Center Expert CDCDP – Certified Data Center Design Professional