Technology Q&A
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IT Infrastructure Management Services
How many tiers are there of data centers?
The Uptime Institute has defined four different tiers of data centers (this definition is most commonly used):
- Tier I (99.67% availability) ~29 hours downtime in a year
- Tier II (99.74% availability) ~23 hours downtime in a year
- Tier III (99.98% availability) ~1.58 hours downtime in a year
- Tier IV (99.995% availability) ~ 0.438 hours downtime in a year
In practice, Tier II and Tier III data centers are the most common.