The Data Center Tier System: Understanding What It Means

Tier 3 data center specifications checklist

Data centers play an essential part in protecting your data. Understanding the data center tier system can help you evaluate where you should host your data. It provides you with insight into the performance and reliability of a data center as well as a host. Data center tiers can be a starting point for discussing which data center provider is best for your organization.

Data center tiers provide a standardized, objective way to evaluate the performance of a data center. The tiers allow you to compare different sites and choose the one that best aligns with your business goals. There are four tiers for data centers. Each one builds on the previous one, incorporating its criteria and adding improved features based on need.

Understanding the Data Center Tier System

The data center tier system is the standard for data center classification and standardization. This includes evaluating important factors such as:

  • Availability
  • Reliability
  • Security 

This system was developed over 25 years ago and has remained the standard for evaluating performance ever since. The different tiers are used to explain what kind of infrastructure will be required to maintain data center operations. As more system availability is needed, a higher tier will be required. 

One of the biggest benefits of having a tiering standard is that its definitions are objective. It provides tried and true methods for comparing infrastructure between sites. This allows you to better align your business goals with infrastructure investments.

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How Data Center Tier Classification Works  

Data center classifications are broken down into four different tiers. Each one operates in one of these tiers and is classified based on a number of criteria. These criteria can be further broken down into two different categories:

  • Topology
  • Operational sustainability

Topology speaks to the functionality of a data center’s infrastructure. These includes criteria such as:

  • Business function
  • Cooling
  • Fault capabilities
  • Maintenance
  • Power

The classification system is progressive, meaning that every subsequent tier level includes the requirements from the lower tiers. In some cases, tiers III and IV are better for certain business operations than lower-tier options. 

Operational sustainability is the human aspect of data center tiers. It takes into consideration the behaviors and risks required to achieve long-term business goals. Successful data center owners can adapt their management strategy to a specific tier in order to achieve operation sustainability.

Are you looking for a fully redundant and fault-tolerant data center that can support and grow your business? Contact us today to start a conversation!


What are the Different Data Center Tiers?

Now that we’ve established how the data center tier system works, let’s look at the tiers individually. Remember that each tier has the same capabilities as those that preceded it. This means that as you move higher in the classification system, you get what each previous tier has to offer plus room to grow.

Tier I

A data center classified as tier I operates at the basic capacity level. While it provides protection from human error, it can’t prevent outages or other unexpected failures. Tier 1 data centers must shut down for a number of reasons such as repairs and preventative maintenance. This helps reduce the risk of unforeseen disruptions and the fallout resulting from system failure.

To qualify for tier I, a data center must have:

  • Room for IT systems
  • An uninterruptible power supply
  • An engine generator
  • Cooling equipment

An uninterruptible power supply (UPS) prevents power outages, spikes, and sags. The engine generator compensates for power outages. Cooling equipment must run outside of office hours to make sure the data center is cooled properly at all times.

Tier II

Along with criteria from tier I, tier II includes:

  • Chillers
  • Cooling units
  • Energy storage
  • Engine generators
  • Fuel cells
  • Fuel tanks
  • Heat rejection equipment
  • Pumps
  • UPS modules

These components serve as redundant capacity components that go beyond what’s required to support the computer equipment. They help ensure that a data center has plenty of cooling and power for improved maintenance and preventing safety disruptions. While an unexpected shutdown will affect the system, components can be removed without requiring a shutdown.

Tier III 

Tier III includes the criteria from tiers I and II. At this level, a data center is maintained with the redundant components from tier II as well as redundant distribution paths that allow traffic to flow without resulting in downtime. Shutdowns aren’t required for equipment replacement or maintenance since any part can be powered down without interrupting operations.

Tier IV

Tier IV improves on tier III by implementing fault-tolerant components to their criteria, which TenHats also provides. It means that the distribution path won’t be interrupted if there’s an interruption or a piece of equipment malfunctions. Fault-tolerant power design is required in all of the IT equipment in order to be compatible. They also feature continuous cooling to keep the data center stable.

This tier features multiple independent systems for redundant distribution paths and components. Having a separate distribution path for power and cooling prevents both systems from becoming compromised. For instance, the power source won’t connect to any external source in case of a local event that would cause one system to be interrupted.

TenHats is home to the first purpose-built data center in Knoxville, TN, in over 20 years. Built to exceed tier III standards, we can serve any business in our region and beyond. At 10,000 square feet and with a 24/7 security staff, we offer:

  • 2n redundancy
  • Around-the-clock support
  • Constant protection
  • HIPAA and SOC II security

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The data center tier system is an objective, standardized method for evaluating data center performance. Each tier gives you the ability to compare different data center sites and determine which best supports your business goals. There are four tiers to choose from, each building on the previous one to provide you with the best security and reduced downtime possible.

In 2016, TenHats built the region’s first purpose-built colocation data center in over 20 years. Located in Knoxville, TN, our data center can serve any organization in East Tennessee and beyond. With our team’s IT experience, we provide a lot more than simply protected data. When you call us, you talk to a real IT expert, not just security. Connect with our team about our data center today!

Picture of Aaron Sherrill

Aaron Sherrill

Aaron is the Chief Technology Officer at TenHats leading the technology, cybersecurity, and data center teams of our organization. He has 25+ years of IT and security experience spanning across a variety of industries, including healthcare, manufacturing, and software development.

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