Datacenter Tiers Classification Level (Tier 1,2,3,4)


Over 25 years ago, the Uptime Institute established the data center Tier categorization levels, which are still the international benchmark for data center performance today. The infrastructure necessary for data center operations is explained in our data center Tier definitions. Tiers are assigned based on the level of system availability required. These categories are objective and dependable techniques for evaluating the performance of one site’s infrastructure to that of another and matching infrastructure investments with business objectives.

Since Uptime Institute is the founder and most trusted source for data center Tier Certification, you can rely on our Tier Certification ratings to assess your capabilities and satisfy your performance criteria. Because we are the only licensed business that can give these certificates, we are the only place where you can get this significant rating.

What Does a Datacenter’s Tier Classification Mean for Its Infrastructure?

The data center Tier definitions specify requirements rather than particular technology or architecture alternatives for achieving the Tier. Tiers are adaptable enough to accommodate a wide range of solutions that fulfil performance objectives and regulatory requirements. Many solutions contribute to data center engineering innovation and individuality. Each data center can choose the optimal method for meeting the Tier requirements and achieving its business objectives.

To satisfy their business needs, data center owners may aim to attain a specific Tier level. Using Tier classification criteria guidelines, Uptime Institute can grade and certify your design and facilities, resulting in a Tier Certification. This accreditation signifies that the infrastructure is fault-free and that the data center is held to a global standard of outstanding.



Datacenter Tiers Levels

Four datacenter tiers levels exist that grow from bottom to top, tier-1, tier-2, tier-3, and tier-4, which are discussed one by one.


Tier-1 data centers are the most necessary infrastructure level for supporting information technology in a workplace and beyond. Tier-1 facilities must meet the following criteria:

  • A dedicated cooling system that operates outside of business hours.
  • In the event of a power loss, a generator is powered by an engine.
  • For power sags, outages, and spikes, use an uninterruptible power supply (UPS).
  • A location for computer systems.

Tier-1 safeguards against human mistakes, but not against unexpected failure or outages. Chillers, pumps, UPS modules, and engine generators are examples of redundant equipment. For preventative maintenance and repairs, the plant will have to shut down completely and failing to do so raises the danger of unanticipated interruptions and catastrophic repercussions from system failure.


Tier-2 structures include redundant services that allow customers for power and cooling, allowing improved maintenance and protection against outages. These elements are as follows:

  • Modules for automatic power supply.
  • Heat rejection apparatus.
  • Tanks for fuel.
  • The use of fuel cells.
  • Generators for engines.
  • The ability to store energy
  • Air conditioners

Tier-2’s distribution channel supports a mission-critical environment, and the assets can be removed without shutting down the system. A Tier-2 data center’s unplanned closure, like that of a Tier-1 facility, will impact the system.


As a significant distinction, a Tier-3 data center maintains advanced systems and redundant distribution channels to service the sensitive environment. Unlike Tier-1 and Tier-2, these operations do not require shutdowns when hardware has to be held or replaced. Tier-3 elements are combined to Tier-2 branches so that any system element may be turned off without disrupting IT operations.


A Tier-4 data center includes many additional capacity components and channels of distribution that are practically segregated and autonomous. The separation is required to prevent both systems from being harmed by a single event. Interruption from planned and unexpected events will not affect the environment. However, if the redundant elements or distribution channels are taken down for repairs, the environment may be more vulnerable to interruption if a breakdown occurs.

Tier-4 facilities improve the Tier-3 topology’s failure tolerance. When a part of equipment breaks or the distribution channel is disrupted, IT activities are unaffected. To be interoperable, all IT hardware must have a fault-tolerant power architecture. Tier-4 data centers also require constant cooling to maintain a stable climate.

Uptime Faculty’s data center categories are well-known as industry benchmarks for data center performance. Tier Certification examines your data center infrastructure and verifies compliance, guaranteeing your clients that your facilities will live up to expectations. Hundreds of businesses have completed our Tier Certification program, acknowledging the value of our categories in data center facilities management.


To conclude, you must evaluate both accessibility and your IT requirements when choosing a data center. Tier-1 and Tier-2 data centers are typically not suited for mission-critical workloads, but if you have no other option and a backup plan in place to govern how the business operates during outages. Only keep your mission-critical workloads in Tier-3 and Tier-4 data centers.

Leave a Reply

Your email address will not be published. Required fields are marked *

home-icon-silhouette remove-button

Connect With Us