Data Centre Tiers
Data centre tiers are the Uptime Institute's four-level classification of data centre resilience, from Tier I (basic) to Tier IV (fault tolerant).
What is Data Centre Tiers?
Tier I has a single path for power and cooling and no redundancy. Tier II adds redundant components. Tier III is concurrently maintainable, so any component can be taken out without downtime. Tier IV is fault tolerant, withstanding any single failure.