Data center tiers are defined levels of resiliency and
redundancy for IT facility infrastructure. They are widely used in the
data center
A data center is a building, a dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommunications and storage systems.
Since IT operations are crucial for busines ...
,
ISP
An Internet service provider (ISP) is an organization that provides a myriad of services related to accessing, using, managing, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, non ...
and
cloud computing
Cloud computing is "a paradigm for enabling network access to a scalable and elastic pool of shareable physical or virtual resources with self-service provisioning and administration on-demand," according to International Organization for ...
industries as part of the engineering design for
high availability
High availability (HA) is a characteristic of a system that aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period.
There is now more dependence on these systems as a result of modernization ...
systems. The data center tier system was created by the
Uptime Institute
451 Group is a New York City-based technology industry research firm. Through its Uptime Institute operating unit, the company provides research for data center operators. In December 2019, 451 Group sold an operating division, 451 Research, to in ...
.
The standard data center tiers are:
* Tier I: no redundancy
* Tier II: partial N+1 redundancy
* Tier III: full N+1 redundancy of all systems, including power supply and cooling distribution paths
* Tier IV: as Tier III, but with 2N+1 redundancy of all systems
A Tier III system is intended to operate at Tier II resiliency even when under maintenance, and a Tier IV system is intended to operate at Tier III resiliency even when under maintenance.
Most commercial data centers are Tier III; instead of using Tier IV datacentres, many large service providers typically use multiple
availability zones to implement of their services, thus achieving greater resilience than would be possible with any single data centre.
See also
*
Availability zone
In cloud computing, an availability zone is a subset of an IT infrastructure system that shares no service-critical components (including power, cooling and access) with any other availability zone. Availability zones are typically geographically ...
References
Data centers
Reliability engineering
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