Data centre tiers
Let’s begin with the definition of data centre tiers. A common misunderstanding is that they are a measure of the size, capacity or maturity of a data centre. Rather, they are a measure of the level of reliability and availability that a data centre facility is designed to provide.
Tier standards are issued by various agencies. The Uptime Institute's Tier Classification System (Tier I to IV) and the ANSI/TIA-942 (Rating 1 to 4) are the most widely recognised and accepted standards for data centre tiers. Both systems define four different levels of data centres, where level 1 is the least reliable with the lowest availability, while level 4 is the most reliable with the highest availability from an infrastructure design perspective. Each tier has its own set of requirements and properties.
While both the Uptime Institute’s tier rating systems and the ANSI/TIA-942 standards are designed to classify data centre reliability and availability, they differ in their approach. The Uptime Institute (UTI) primarily focuses on the design of mechanical and electrical critical infrastructure. The ANSI/TIA-942 standard covers a wider range of aspects related to data centres, including not only the design, mechanical, and electrical critical infrastructure but also the network, architectural, and operational considerations. This means that the standard incorporates other important areas such as security, architecture, and telecommunications.
The two standards share a common ground despite their differences. Initially, the Telecommunication Industry Association (TIA) released TIA-942, in partnership with the American National Standards Institute (ANSI), using the same tier levels. However, this led to confusion, prompting TIA to revise their tier levels to rating levels.
In this blog post, we'll discuss the specific requirements for your data centre by examining the various tier levels according to the Uptime Institute. So, what exactly are these tier levels? Read on to find out.
Uptime Institute Tier Standard Topology (TST)
To get a quick overview of the differences between the Tier Standard Topology, a summarising overview can be found below. For a more comprehensive understanding of each tier level, we'll provide a short clarification of each Tier level.