Data Center Strategies for the CIO
The Uptime data center tier standards are a standardized methodology used to determine availability in a facility. The tiered system, developed by the Uptime Institute, offers companies a way to measure return on investment (ROI) and performance. The standards are comprised of a four-tiered scale, with Tier 4 being the most robust. See the table at the end of the definition for an illustration of the differences between the four tiers.
The Uptime Institute offers a certification process to address the issue of companies advertising loosely-interpreted and unverified claims of certification. As of the beginning of 2008, more than two dozen data centers had been certified by the Institute. The certification process begins with a desktop review of submitted design documents by licensed engineers at the Uptime Institute. The review is followed by a site visit where Uptime employees examine whether a facility had been built or expanded according to the submitted design. The Uptime Institute has also released a grading system for operational sustainability to augment the tier standards. The tiers focus on the design of the data center facility; the operational sustainability grades target how well the facility is actually run.
| Tier level | Data center requirements |
| Tier 1 | 1) A single, non-redundant distribution path serving IT equipment. 2) Non-redundant capacity components. |
| Tier 2 | 1) All Tier 1 requirements. 2) Redundant capacity components. |
| Tier 3 | 1) All Tier 1 and 2 requirements. 2) Multiple independent distribution paths serving IT equipment. Generally, only one distribution path serves equipment at any given time. 3)
All IT equipment is dual-powered and fully compatible within the topology of a site's architecture. |
| Tier 4 | 1) All Tier 1, 2 and 3 requirements. 2) The facility is fully fault-tolerant, through electrical, storage and distribution networks. 3) All cooling equipment is independently dual-powered, including HVAC systems. |