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May 08, 2014

What do the different tiers of a data center indicate?

I often see data centers categorized by tier (tier 1, tier 2, tier 3, tier 4). What is the difference between the various tiers?

05/13/2014
http://www.webopedia.com/TERM/D/data_center_tiers.html

"Tier 1: composed of a single path for power and cooling distribution, without redundant components, providing 99.671% availability.
Tier II: composed of a single path for power and cooling distribution, with redundant components, providing 99.741% availability
Tier III: composed of multiple active power and cooling distribution paths, but only one path active, has redundant components, and is concurrently maintainable, providing 99.982% availability
Tier IV: composed of multiple active power and cooling distribution paths, has redundant components, and is fault tolerant, providing 99.995% availability."
05/10/2014

Basically, the higher the number, the greater the level of redundancy and compartmentalization. There is a nice, plain English summary at cybercity.biz.

 

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.

http://www.cyberciti.biz/faq/data-center-standard-overview/

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