Stop! Do you have a need for a new data center or expansion of your existing data center space? Assuming that the due diligence has been done as it relates to the needs analysis for the additional space, the first thing you need to consider is what, where, and how will that space be determined to support the specialized needs of a data center. If you are considering a retrofit of an existing facility, then assessing the physical infrastructure required to support a Tier II, III, or IV data center is critical. The tier level of your data center is directly related to its function and the reliability requirements as identified by your Information Technology management.
Data center tier levels
Tier classification is an industry recognized qualification as defined by the “The Uptime Institute” for data center redundancy and reliability at http://www.uptimeinstitute.org:
Tier I: Basic data center. Basic data centers are composed of a single path for power and cooling distribution, without redundant components. They may or may not have a raised floor, Uninterruptible Power Supply (UPS), or an engine generator, and if they do, they are single module systems with many single points-of-failure. A Tier I data center is susceptible to disruption from both planned and unplanned shutdowns.
Tier II: Redundant Components. These data centers are composed of a single path for power and cooling distribution with redundant components that are slightly less susceptible to disruptions than a basic data center. They can have raised floors, UPS, and engine generators, but they are on a single-wired distribution path throughout. Tier II data centers require planned processing shutdowns.
Tier III: Concurrently Maintainable. These data centers are composed of multiple active power and cooling distribution paths, but only one active path has redundant components and is concurrently maintainable. This level allows for planned infrastructure activity without disrupting the computer hardware operation. Planned activities include preventative maintenance, repair and replacement of components, addition or removal of capacity components, testing of components, and more. Sufficient capacity and distribution must be available to simultaneously carry the load on one path while performing maintenance on the other. Unplanned activities or errors can still cause disruptions, but Tier III data centers provide 99.982% availability.
Tier IV: Fault Tolerant. These data centers are composed of multiple active power and cooling distribution paths, have redundant components, and are fault tolerant, providing 99.995% availability. Fault tolerant functionality provides the ability of the site infrastructure to sustain at least one worst-case unplanned failure or event with no critical load impact. Two separate UPS systems are required and all computer hardware in required to have dual inputs.
