How Does the Data Center Tier System Work?

The marketing language around data centers can be filled with buzz words like “top tier” and “tier 4 data center.” But what do data center tiers actually mean and how does it impact your business? In this article, we’ll outline what each data center tier means so you can make an informed decision.
See Also: An Overview of ServerMania Data Centers
What Are Data Center Tiers?
The Uptime Institute developed a standard by which data centers are graded based on the redundancy mechanisms that are in place within the facility. Each data center can then be placed in a specific tier from 1 to 4. Tier 1 data centers feature the least amount of redundancy, whereas Tier 4 have every redundant mechanism expected for the highest possible uptime.
Key Terms
The following key terms are helpful in understanding the breakdown of the data center tiering system:
Capacity Component: Include items such as uninterruptible power supply, cooling systems and auxiliary generators.
Distribution Path: The connection path that a capacity component follows in order to service a server. For example, a power line which feeds from the utility service to a server rack.
Data Center Tier Summary
Here is a summary of each of the data center tiers. Below we will explore each tier in more detail and what the components mean:

Source: Uptime Institute
Tier 1
Data centers in the Tier 1 category feature the lowest amount of redundancy and are susceptible to downtime during planned
Uptime: 99.671%
Power: A single, non-redundant power connection to service the facility.
Cooling: Dedicated Cooling Equipment
Fuel Storage: 12 Hours
Tier 1 facilities must also have a UPS to filter power spikes, sags, and momentary outages. There must be sufficient power capacity to meet the needs of the data center,
A Tier 1 facility is likely to offer the lowest cost server hosting due to the lack of redundant hardware to setup and maintain. As such, it is a good option for data that doesn’t need to be 100% accessible such as cold storage for backups.
Tier 2
Data centers in the Tier 2 category feature redundant capacity components with a single distribution path servicing the data centers.
Uptime: 99.741%
Power: Redundant power such as an engine generator or fuel cells
Cooling: Redundant Chillers / heat Distribution Equipment and Dedicated Cooling
Fuel: 12 Hours of On-Site Storage for N Capacity
UPS: Redundant Modules
Individual components can be taken offline for maintenance in a Tier 2 data center without any downtime, but servers may go offline if the distribution path needs to be taken offline for any reason.
A scheduled yearly downtime would be common in Tier 2 data centers as every component should be shutdown for routine maintenance. Without a redundant distribution path, this will often result in server downtime being required.
Tier 3
Data centers in the Tier 3 category feature both redundant capacity components (cooling, power, etc.) as well as independent and redundant distribution paths.
Uptime: 99.982%
Power: Redundant power such as an engine generator or fuel cells. Multiple distribution paths to servers that are independant.
Cooling: Redundant Chillers / heat Distribution Equipment and Dedicated Cooling
UPS: Redundant Modules
Fuel: 12 Hours of On-Site Storage for N Capacity
All servers in a Tier 3 data centers are redundantly powered to the two distribution paths in order to ensure that servers remain online in the event of one distribution path going offline.
Tier 4
Data centers in the Tier 4 category feature the highest level of redundancy across all levels. These data centers are considered fault tolerant and feature multiple independent, compartmentalized and physically isolated systems to provide redundant capacity components and multiple diverse and independent paths which feed the servers.
Uptime: 99.995%
Power: Redundant power such as an engine generator or fuel cells. Multiple distribution paths to servers that are independant.
Cooling: Redundant Chillers / heat Distribution Equipment and Dedicated Cooling
UPS: Redundant Modules
Fuel: 12 Hours of On-Site Storage for N Capacity

Choosing A Data Center
The data center tiering system begs the question, “why aren’t all data centers tier 4, and why wouldn’t I choose the most redundant option?” This is a fair point. But the reality is that Tier 4 data centers are not always available in each region and they do come with an increased cost.
Maintaining and deploying all of the redundant components in a Tier 4 data center is very costly, and as such, hosting servers in a tier 4 data center can be more expensive. You also need to choose a data center in the right geographic region for your project.
ServerMania partners with Tier 3 and Tier 4 data centers in order to ensure maximum uptime for your next server project. We also offer a 100% network uptime SLA to host even the most mission critical business applications. Book a free consultation today and find out how ServerMania Tier 3 and Tier 4 data centers can empower your business.