Data center tiers are a classification system, ascending 1, 2, 3, and 4 – with some operators even pushing for 5 – that are used to evaluate data center facilities, consistently, regarding their potential site infrastructure availability , also known as uptime . Specifically, the tier ratings stipulate what a data center can offer in terms of redundancy and resiliency , as well as how much potential downtime a customer could experience for a year. As a general rule, the difference between data center tiers is that tier 1 offers no redundancy of any critical system, tier 2 has partial redundancy in their electrical & HVAC systems, tier 3 contains dual redundancy for power & cooling equipment, and tier 4 possesses fully redundant infrastructure. Data centers are commonly rated by the Uptime Institute , an independent organization, which has issued over 2,500 certifications to data centers in more than 110 countries. The Upt...