Data Center Tiers
Data centers are classified with a system called Tiers. Tiers describe specific data center infrastructure in a consistent way for comparing them against one another.
Data Center Classifications
Tier classification system explains the infrastructure required for data center operations. There are four (4) different Tiers ranking data center infrastructure systems availability in terms of maintenance, power, cooling and fault capabilities.
The four Tiers are Tier I, Tier II, Tier II and Tier IV. Tier I data center has the simplest infrastructure and Tier IV the most complex, with the most redundant components. The Tiers are progressive and each Tier incorporates the requirements of the lower Tiers.
Although a Tier IV data center has more maintenance, power, cooling and fault capabilities, it does not mean it is best-suited for your needs. While using a colocation at a Tier I data center could leave your business open to a risk of having unscheduled downtimes, using a colocation at a Tier IV data center could be an over-investment.
Topology and operatinal sustainability
There are two essential components of data center Tier classifications, topology and operational sustainability.
Topology focuses on the data center infrastructure and defines criteria for maintenance, power, cooling and fault capabilities.
Operational sustainability refers to the behaviors and risks apart from infrastructure design that determine the ability of the data center to meet long-term business goals.
Together, topology and operational sustainability establish the performance criteria you can use to judge which data center is best for your business or research computing needs.
The data center Tier definitions define what should be implemented in order to reach a certain Tier level, but not how to implement it. The implementation details, including design choices and technology options, are left to each data center to decide on.
Each data center can meet a certain Tier criteria in a different way, but they all satisfy the same required performance goals and compliance regulations.
Data Center Tier Levels
Data Center Tier levels start at Tier I. Tier I data centers have the basic infrastructure components including a dedicated area for IT equipment with 24/7 cooling, UPS and a power generator.
To decrease the risk of unplanned disruptions that can be fatal to IT equipment, data centers have to schedule preventime maintenance to do repairs. Since they lack enough redundant equipment, to perform preventive maintenance Tier I data centers must shut down completely.
Tier II data centers have everything Tier I data centers have. In addition, they have additional data center power and cooling redundancy equipment to enable easier maintenance and safety against disruptions.
Still, Tier II data centers can have unplanned downtime, in which case the data center and its customers will be affected.
Tier II data centers have everything Tier II data centers have. In addition, they have enough redundant power and cooling equipment to replace, update and maintain those infrastructure components without the need to shut them down. Tier III data centers are called /cuncurrently maintainable/. (in italics).
In addition to Tier III capabilities, Tier IV data centers are built to be completely fault tolerant and have redundancy for every infrastructure component.
Tier IV data center will not be affected by a disruption from planned and unplanned events. As a result, IT operations will not be affected when a piece of data center infrastructure fails.
Data centers are classified with a system called Tiers.
Tiers describe specific data center infrastructure in a consistent way for comparing them against one another.
Tier I data center has the simplest infrastructure and Tier IV the most complex, with the most redundant components.
Although a Tier IV data center has more maintenance, power, cooling and fault capabilities, it does not mean it is best-suited for your needs.
Use the data center Tiering system to help you select the right data center for your needs, but don’t select a data center based only on its Tier.