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Standards & Classifications

Uptime Institute Tier Classification

Tier I–IV

Four-level system rating data centre design resilience from basic (Tier I) to fault-tolerant (Tier IV).

Full Definition

The Uptime Institute Tier Classification rates data centre infrastructure in four levels. Tier I (99.671 % uptime, ≤28.8 h downtime/year): single path, no redundancy. Tier II (99.741 %, ≤22 h): redundant components, single distribution path. Tier III (99.982 %, ≤1.6 h): concurrently maintainable. Tier IV (99.995 %, ≤26 min): fault-tolerant. Tier III is the most common certification for mission-critical colocation.

Also Known As

tier classificationtier 1tier 2tier 3tier 4uptime institute

Source Reference

Uptime Institute — Tier Standard: Topology (2022)

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