Recently, some of our Canadian Web Hosting customers have been inquiring about Data Centre Tiers and what the benefits are for each type of facility.  First off, in looking at “tiers” it is important to recognize that by definition Tier 1 to Tier 4 data centres is nothing more than a standardized methodology used to define uptime of data centre.  The reasons for this is that it allows customers to measure three distinct, but equally important criteria:

a) Data centre performance
b) Required Investment
c) Return on Investment

In looking at the different tiers, Tier 4 data centres are considered to be the most robust and less prone to failures. Tier 4 data centres are designed to host mission critical servers and computer systems, with fully redundant subsystems (cooling, power, network links, storage etc). In addition, these data centres offer security zones that are controlled by biometric access controls methods.   Some of these same requirements also play a significant role in our yearly audits.  For Canadian Web Hosting’s most recent SSAE 16 Type II SOC 1 audit, we had to look at the physical security, as well as the layout and make up of the data centres.  This plays a significant role and is a requirement in order to receive that audit certification.  As a comparison, the simplest is a Tier 1 data centre that are used often times by small business’ that don’t have corporate governance requirements mandating certain uptime and performance metrics.  

Here is a breakdown of constitutes the different Tiers:

Tier 1 = Non-redundant capacity components (single uplink and servers).

Tier 2 = Tier 1 + Redundant capacity components.

Tier 3 = Tier 1 + Tier 2 + Dual-powered equipment and multiple uplinks.

Tier 4 = Tier 1 + Tier 2 + Tier 3 + all components are fully fault-tolerant including uplinks, storage, chillers, HVAC systems, servers etc. Everything is dual-powered.

Data Centre Availability According To Tiers

With all of the different Tiers, probably the most significant question that comes up is what is the availability of those data centres and what tier is the most appropriate for your business.  Here are the levels describing the availability of data from the hardware at a location as follows:

Tier 1: Guaranteeing 99.671% availability.

Tier 2: Guaranteeing 99.741% availability.

Tier 3: Guaranteeing 99.982% availability.

Tier 4: Guaranteeing 99.995% availability.