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17Dec 2016

Data Centre Tiers Explained

In this post we explain the difference between a Tier 1, Tier 2, Tier 3, and Teir 4 Data Centre.

The Tier number (1 to 4) defines the resilence and uptime of the centre. Tier 4 data centres are considered the most robust and least prone to failures. Tier 4 is designed to host mission critical servers and computer systems, with fully redundant subsystems (cooling, power, network links, storage etc) and compartmentalized security zones controlled by biometric access controls methods.

Tier 1 = Non-redundant capacity components (single uplink and servers).

Tier 2 = Tier 1 + Redundant capacity components.

Tier 3 = Tier 1 + Tier 2 + Dual-powered equipments and multiple uplinks.

Tier 4 = Tier 1 + Tier 2 + Tier 3 + all components are fully fault-tolerant including uplinks, storage, chillers, HVAC systems, servers etc. Everything is dual-powered.

Data Center Availability According To Tiers

The levels also describes the availability of data from the hardware at a location as follows:

Tier 1: Guaranteeing 99.671% availability.

Tier 2: Guaranteeing 99.741% availability.

Tier 3: Guaranteeing 99.982% availability.

Tier 4: Guaranteeing 99.995% availability.