Data Center Tier definition & meaning
Data center tiers are used for explaining specific kinds of data center depending on specific features. Tier certification proves some features of a data center such as respect, guidance, risk avoidance, higher efficiency. Uptime Institute’s Tier Standard Certification is considered as an industry standard for design, construction, and ongoing operations. Data center tier uses methods for comparing the performance of one site infrastructure against another and aligning infrastructure investments to business goals. There are four Tier Standard of Uptime Institute (often displayed with Roman Numerals), regarding the criteria for maintenance, power, cooling, and fault capabilities.
A Tier I data center is the basic capacity level with infrastructure to support IT. A Tier 2 data center offers better maintenance opportunities and safety against disruptions by providing engine generators, energy storage, chillers, cooling units, UPS modules, pumps, heat rejection equipment, fuel tanks, and cells. A Tier III data center has multiple paths for power and cooling and systems as a key differentiator, with redundant distribution paths to serve the critical environment. A Tier 4 data center is built to completely fault-tolerant and has redundancy for every component. These fault-tolerant facilities have an expected uptime of 99.995%. This means 26.3 minutes of downtime annually. A data center can be issued Tier 4 certification by providing several independent and physically isolated systems.