Redundancy levels and tier classifications

Skills you'll practise

• Calculate N for a load and unit size, and state whether installed units are N, N+1 or 2N, including during maintenance
• Distinguish redundant capacity components from redundant distribution paths, and concurrent maintainability from fault tolerance
• Describe Uptime Institute's four Tiers by their public names and say what a Tier claim does and doesn't prove
• Find single points of failure on a simplified one-line diagram
• Explain redundancy and maintenance risk to a customer accurately, without promising zero risk

Course outline

1. 1.Redundancy and Tiers without the mythsVideo · 2 min
2. 2.N, N+1 and 2NLesson · 16 min
3. 3.Components, paths and the Tier namesLesson · 18 min
4. 4.Single points of failure and talking about riskLesson · 16 min
5. 5.Redundancy levels and tier classifications: knowledge checkKnowledge check · 18 questions
6. 6.Redundancy levels and tier classifications: practical exerciseKnowledge check · 1 question
7. 7.Final exam9 questions · passing it completes the course, so people who already know the material can test out

Sources it draws on

The lessons and questions are written from these references, so learners can go back to the original.

• Uptime Institute: Tier Classification System (public overview of Tiers I-IV)
• Uptime Institute Journal: Explaining the Uptime Institute's Tier Classification System (April 2021 update)
• Uptime Institute: Tier Standard: Topology (abstract)
• TIA: ANSI/TIA-942 Telecommunications Infrastructure Standard for Data Centers (overview page)
• U.S. DOE Federal Energy Management Program: Best Practices Guide for Energy-Efficient Data Center Design (2024), incl. ASHRAE 2021 thermal guideline table, cooling, electrical and metrics sections
• ASHRAE TC 9.9: Data Center Power Equipment Thermal Guidelines and Best Practices (2016), incl. the 2015 thermal guideline table and notes, power distribution chain, RPPs and busways
• General data-center facilities operations practice