Data centres are primarily classified based on a Tier system that measures their reliability and redundancy levels.
This classification indicates the expected uptime and the resilience of the infrastructure to failures. The most widely recognized classification system assigns data centres to different Tiers, from Tier 1 to Tier 4. Each Tier builds upon the requirements of the lower Tier, offering increasing levels of reliability and fault tolerance.
Data Centre Tier Classifications
The classification system helps businesses choose a data centre provider that meets their specific needs for availability and business continuity. Here's a breakdown based on standard classifications, including details from the provided reference:
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Tier 1:
- A Tier 1 data center has a single path for power and cooling.
- It includes few, if any, redundant and backup components.
- It has an expected uptime of 99.671% (equivalent to approximately 28.8 hours of downtime annually).
- This is the most basic level, offering limited protection against disruptions.
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Tier 2:
- A Tier 2 data center has a single path for power and cooling.
- It includes some redundant and backup components.
- This Tier provides slightly better reliability than Tier 1 due to the inclusion of redundant components, reducing the risk of downtime from single equipment failures.
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Tier 3: (Requires additional redundant capacity components and multiple independent paths for power and cooling)
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Tier 4: (Requires fault tolerance, meaning any single failure event should not impact critical operations)
These classifications ensure that organizations can align their infrastructure requirements with the capabilities and guaranteed uptime of a data centre facility. Understanding these Tiers is crucial for managing risk and ensuring continuous operation of critical IT services.
