Data Center Tiers: Guide to Tier Classification System

data center tiers

Last Updated on October 5, 2021 by Josh Mahan

Data centers are a leading force that powers the global economy. They house the systems, devices, applications, and data that make it possible to do business in modern society.

Specialists predict that the total number of data centers globally surpasses 8.4 million, with more than 3 million in the U.S. Thanks to the Internet and online business expansion, that total has grown dramatically over the past two decades. However, some analysts maintain that the number of data centers could decrease due to the rise of the public cloud and co-location. Workloads are moving into fewer, more comprehensive data centers, including those run by the world’s largest technology corporations.

Understanding data center tiers and types help I.T. teams differentiate between the productivity, uptime, construction, and design of each tier and class. The tier classification system can be helpful for businesses in aligning their intentions with their data center’s goals.

What Is a Data Center?

A data center is a facility or building that houses hundreds, if not millions of square feet of area of centralized computer and telecommunications systems.

A typical data center includes various I.T. infrastructure, including servers to provide computing power, networking equipment to connect the systems to the Internet or storage, and of course, cleaning

A large data center requires various supporting systems to allow the I.T. infrastructure to function properly. To function correctly, they need:

  • An uninterruptible power supply (UPS) that provides enough electricity for all the computers housed in the facility. 
  • Ventilation.
  • Cooling systems.
  • Connections to external networks.
  • Back up generators and diesel to keep them running.
  • An electrical grid and generators in case of a power outage.

Data centers also need control centers where staff can monitor the performance of the servers and the physical plant. They also need to have security measures that strictly control access to the facility to avoid malicious infiltrators.

Related: Data Centers: What They Do & Why [2021]

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What Are Data Center Tiers?

The Uptime Institute placed the tier classification system in 2005 to produce transparency on a data center’s redundancy. The uptime and performance of a company’s data center are crucial features of modern businesses.

Experts can find and address incompetence in their current systems using the tier guidelines to evaluate and improve uptime. 

Suppose you are not soliciting a certified tier level. In that case, you can still find it helpful to reference the tiers as you consider how to structure your data center to satisfy your business needs.

This system sets data center tier models to produce four distinct data center redundancy tiers: Tier IV, Tier III, Tier II, Tier I. Each tier is tightly defined based on various determinants, including:

  1. Maintenance protocols. 
  2. Data center redundancy levels.
  3. Staff expertise.
  4. Uptime guarantee.

Tier levels help provide insight into the minimum performance and availability expected of data centers within a tier. The capacities of a data center increase as you go from Tier I, referring to the least reliability, to Tier IV, with the maximum reliability possible. 

Each tier includes the conditions of the previous level as you ascend the tier ladder. Knowing the capacities at each level can help you align your needs with a correctly executed data center. 

Related: Data Center Infrastructure: What You Need To Know

Data Center Tiers

Tier 1

Tier 1 data centers are more than just staging your servers in a spare office or huge closet inside a larger plant.

Tier 1 data centers have:

  • A single, non-redundant distribution path serving I.T. equipment
  • Non-redundant capacity components.
  • Dedicated space for all I.T. systems
  • Constant power supplies to prevent spikes from damaging equipment
  • A controlled cooling control environment that runs 24/7
  • A generator to keep equipment running during a power outage

Tier 2

A tier 2 data center combines all the characteristics of tier 1. However, it also includes some partial redundancy in power and cooling elements (the power and cooling methods are not redundant). 

A tier 2 tops tier 1 requirements, giving extra insurance that power or cooling requirements won’t shut down processing.

Important Notes of a Tier 2 Data Center,

  • All Tier 1 requirements.
  • Needs to remove the distribution paths from service for support or other activities requiring the shutdown of the computer devices.
  • The equipment will be susceptible to disruption from both planned activities and unplanned events. Performance failures may also disrupt the data center.
  • Must have non-redundant capacity parts and a single, non-redundant configuration path servicing the IT equipment.

Tier 3

Tier 3 joins all the features of tier 1 and tier 2 data centers. A tier 3 data center also needs to be able to shut down any power and cooling devices servicing D.C. for maintenance without harming your I.T. processing. 

Redundant cooling systems must also be able to keep functioning even if one cooling unit fails. If one cooling unit fails, then the other one kicks in and continues to cool the room. Tier 3 are not fault-tolerant as they may share separate components such as utility company feeds and external cooling system parts that reside outside the data center.

Important Notes of Tier 3 Data Center,

  • It requires all of tier 1 and 2 components.
  • Generally, only one distribution path serves equipment at any given time.
  • Can perform planned site infrastructure maintenance using redundant capacity components and distribution paths to safely work on the remaining equipment.

Tier 4

A tier 4 D.C. incorporates all the capabilities found in tiers 1, 2, and 3. In addition, all tier 4 power and cooling parts are taken care of by two different utility power suppliers, two separate cooling systems powered by additional utility power services, two UPS systems, two power distribution units (PDUs), and two generators. 

If any power or cooling infrastructure part fails in tier 4, processing will continue without a problem. However, if two different components from two separate electrical or cooling paths fail, then I.T. processing can be affected.

Important Notes of Tier 4 Data Center,

  • It requires all of tier 1,2,3 components. 
  • All IT equipment must be dual-powered and appropriately installed to be compatible with the topology of the site’s design.
  • The facility is fully fault-tolerant through storage, distribution networks, and electrical.
  • All cooling equipment, including HVAC systems, is independently dual-powered.
  • The system responds automatically when a failure happens to prevent further impact on the facility.
  • A Fault-Tolerant data center will have multiple, independent, physically isolated systems. Each has redundant capacity components and multiple, separate, active distribution paths simultaneously serving the computer hardware.
  • A single failure of any capacity system will not affect the computers.

Looking for a high-quality provider to keep your data center up and running with the latest technologies? Contact our data center specialists or view our services here!

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How to Choose the Correct Tier

Data centers are not obliged to follow a Tier Classification System Ranking to do business. However, having a specific tier ranking does help legitimize its services.

The majority of centers that have an official classification are considered to be part of enterprise-level facilities. 

If you are searching for a provider, make sure that any ranking you see comes directly from the Uptime Institute. Although many companies use Uptime Institute ranking criteria for their internal uniformity, this does not mean that the Institute has vetted them personally. For that reason, it is helpful to get expert assistance from a verified provider, like Alterum Technologies, when choosing a data center.

The investment in building out a Tier 4 level facility can be pretty significant. So, the clientele that requires a Tier 4 facility will also have the budget to sustain residence. 

Related: Alterum Technologies Core Values

Let Alterum Help You Build Your Data Center

Each of the four data center tiers shows a specific and increasing performance, redundancy, and complexity. Following tier guidelines, businesses can customize their data centers to meet particular industry goals to establish reliability, ensure the highest uptime, and more.
Are you in need of professional guidance to make your next business decision related to data centers? Contact Alterum Technologies today!

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