Tier 1 to 4 data center is nothing but a standardized methodology used to define uptime of data center.
Tier 4 data center considered as most robust and less 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. Naturally, the simplest is a Tier 1 data center used by small business or shops.
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.
See the below Datacenter Tier attribute chart for more detailed information.
This is useful for measuring:
a) Data center performance
b) Investment
c) ROI (return on investment)
