The need for a globally recognized set of Tier Performance Standards became unavoidable in the mid-1990s. The data center industry was growing at an unprecedented rate as the number of businesses with significant Internet needs skyrocketed. In response to this critical need, the Uptime Institute developed a Tier Classification and Certification System for data centers. This classification system was designed to be used as a standard, globally recognized methodology for measuring data center performance. In this progressive system, each tier adds to the previous level’s requirements. Therefore, Tier II must meet all Tier I requirements before adding to the capabilities.
Choosing the data center tier most suited for a business’s data center necessitates an understanding of the Uptime Tier Classification System. The four tiers are outlined below.
The Uptime Institute’s Tier Classification System
1. Tier 1 / Basic Capacity. A Tier I data center is the most basic of the tier capabilities. Best suited for small businesses and blog hosting, Tier I data centers operate with a single uplink and server. The center provides businesses with a dedicated space for IT systems, an Uninterrupted Power Supply (UPS), cooling equipment, and an engine generator to meet basic backup needs in the event of system failure.
2. Tier II / Redundant Capacity Components. Tier II centers add redundant capacity components to the basic capabilities of a Tier I center. In Tier II centers, businesses are provided with redundant power and cooling capabilities that include UPS Modules, chillers, pumps, and energy generators.
3. Tier III / Concurrently Maintainable. A Tier III center builds upon the Tier II module by adding a redundant delivery path for power and cooling. This enables every component of the Tier III IT system to be shut down for maintenance or repair without impacting the overall IT operation.
4. Tier IV / Fault Tolerance. Tier IV data centers are recognized as the most reliable and secure centers for businesses with high availability requirements. Tier IV data centers build upon the requirements of Tier III centers by adding the concept of Fault Tolerance to their capabilities. Fault tolerance capability means that, in the rare event of an individual system failure or path interruption, the effects of these disruptions do not reach the IT operations. Single or concurrent system or pathway failures will not result in downtime to the entire system.
Understanding Tier IV Data Centers
Choosing the most suitable data center tier for a business depends primarily on two factors – availability and security needs. Businesses with high availability requirements are best suited for the offerings of a Tier IV Data Center. E-commerce, financial settlement companies, and large-scale corporations are generally ideal candidates for Tier IV Data Centers. For businesses in the process of choosing a data center, a brief explanation of the importance of Tier IV Data Center capabilities on your business’s health is provided below.
Tier IV Data Centers have capability levels that are designed to host “mission critical” servers and computer systems. Data centers in this tier are nearly equivalent to the data centers used by the United States government. The outstanding characteristic of Tier IV Data Centers is the concept of Fault Tolerance. In a Tier IV Data Center, every single component of an IT system is dual powered. This means that everything from servers to HVAC systems are operated on multiple distribution pathways. These pathways have the capability to serve each of the components of a site’s computer equipment simultaneously while allowing for complete redundancy in operation and backup. In the unlikely event of a system or pathway failure, the system will automatically respond to prevent future failures at the location. Furthermore, Tier IV Data Centers offer 2N+ Redundancy. This means that each Tier IV Data Center contains two times the amount of power capabilities needed to operate, plus an additional backup generator. As a result of these redundancy capabilities, Tier IV Data Centers offer less than 27 minutes of downtime a year – with each of the downtime events lasting less than a fraction of a second.
Choosing The Ideal Data Center
When it comes to choosing the ideal data center for a business, the primary consideration is the need for data availability and the ability to tolerate downtime without significant impact on the business’s operations and vitality. For small businesses, a Tier I Data Center will provide the basic IT components required to successfully function. For large-scale corporations dealing with high availability and increased security needs, a Tier IV data center is the recommended option.