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Data Center Tiers

What Are Data Center Tiers?

Data center tiers are system used to classify data centers based on several factors, including uptime, redundancy, availability, security, efficiency, and cost. Each Tier represents the level of infrastructure organizations receive. Understanding data center tiers can help organizations choose one that suits their requirements.

What are the 4 Data Center Tiers?

The four data center tiers need to meet the following uptime and redundancy standards to be certified. Generally, the higher the tier, the more the data center will cost:

Tier 1: No redundancy, 99.671% of uptime (approx. 28-29 hours per year of downtime)

Tier 2:  Partial redundancy, 99.741% of uptime (approx. 22 hours per year of downtime max)

Tier 3: Comprehensive redundancy, 99.982% of uptime (less than 1.6 hours per year of downtime)

Tier 4: Fault-tolerant, 99.995% of uptime (less than 0.5 hours per year of downtime)


Fault tolerance, met at the highest data center tier, means that even if there is a failure in one of the components of the data center, no matter the data center location, operation will be able to continue due to there being redundancy measures available for all critical systems. This includes redundancies for power, networking, and cooling.

How Do Data Center Tiers Work?

Uptime Institute doesn't automatically certify or classify data centers. Instead, data centers need to pursue certification and receive a comprehensive assessment by Uptime Institute, which will place them in a given tier category. This process includes a self-assessment and an onsite assessment. Once certification is complete, it will be valid for three years before there is a need to re-certify.

Why Are Data Center Tiers Important?

The data center tiers serve as a shorthand for organizations looking to house their data with certain assurances for reliability and redundancy. Choosing a data center tier that meets compliance needs and, overall, makes sense for your business is all about managing the level of risk you can afford to take on with the cost that is associated with established standards.


For some businesses, every second down counts. Losing reliable access, even for a few minutes, could mean significant differences in revenue or trust. This can be especially true for healthcare entities, financial institutions, and government organizations. Other types of businesses, such as retail establishments or media companies, may not need levels of availability that are quite as high, so they might be able to get away with choosing a lower-tier data center and reducing their costs.

How Are Data Center Tiers Rated?

The ratings for data center tiers are progressive, meaning that if a facility is rated at Tier III, it meets all the requirements for Tier I and Tier II automatically. Specific technology doesn't go into the rating. Instead, general standards for fault capabilities, maintenance, power, and cooling are considered. Management style and behavior are also factors considered in operational sustainability. Aside from infrastructure, data center management should reflect behaviors that demonstrate the facility will be able to meet a certain tier level of standards.

How TierPoint Can Help You Choose a Data Center

Choosing a data center tier is one part of several interconnected decisions you'll have to make when deciding on the data center that is perfect for your business. You don't have to make this choice on your own. TierPoint offers 40 state-of-the-art, interconnected data centers across the country that offer direct connections to cloud providers, carrier-neutral connectivity, and redundant infrastructure. The majority of our data centers offer the ability to connect to customers faster via edge computing and low-latency connections.

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