The Tier Model for Mission Critical Facilities, created and governed by The Uptime Institute, is the most pervasively referenced data center tier model. It is, however, not the only tier model for data center facilities, though it enjoys the majority of mind-share in this regard. We have written about The Uptime Institute’s data center tier model rather extensively in this forum.
The four-tier model from The Uptime Institute was developed through thoughtful analysis and extensive empirical data from facilities of member organizations. One of the reasons that enterprises have gravitated to this model is that it gives guidance as to what level of availability is necessary for certain business models and business characteristics. While this is helpful, the level of abstraction of this framework of guidance is high. A coarse application of guidance can lead to inaccuracy of planning. In the case of data center projects, this exposes the possibility of over building or at least spending that is not accurately targeted. For example, a coarse application of these guidelines could cause planning for a facility designed for one segment of the business’ applications at the expense of all the other enterprise applications.
Interesting also is the fact that while a facility may be uncertified or even non-certifiable to a particular tier level, its true availability performance often outperforms even higher tier ratings (especially in the case of quality providers). The Uptime Institute model has sometimes drawn criticism because it excludes factors contributing to operational excellence, as well as risk management factors that vary significantly based on geographic location alone (as well as other things). The Uptime Institute is working on modifications to its guidance for precisely these reasons, and we look forward to those developments.
In the mean time,we now have the new BICSI-002 standard released (finally) in June 2010. The newly released standard is “BICSI-002-2010, Data Center Design and Implementation Best Practices.” This document is long awaited by the industry, and will likely be adopted as an ANSI standard as well. The document contains advice relevant to IT telecommunications management, security management, operations management, facilities, A&E, and Construction.