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benefits of tier 3 data centre

Exploring the Benefits of Tier 3 Data Centres

We owe much to the massive network of data centres that make the world go round. The features of Tier 1, 2, 3, and 4 data centres may differ, but together they’re the backbone of the internet. In this post, we’ll highlight the benefits of Tier 3 data centres.

This blog post can serve as exhibit A.

Without data centres this blog post, and the interwebs as we know it for that matter, wouldn’t exist.

Our aim with this post is to show you why data centres are important.

What are data centres and why are they important?

In a nutshell, data centres are facilities that house data and other critical applications or software. 

Chart showing the expected growth of the colocation market over the next few years.

The design of a data centre is focused on optimal performance and networking between servers. Of course, the higher up the tiers you go the stricter the protocols for optimization. 

Some of the key features of data centre design are:

  • Switches
  • Firewalls
  • Routers
  • Servers
  • Storage systems
  • Application-delivery controllers.

All these components work together to keep the world wide web working as is. For you, these components keep your website online 24/7. There are cases where your website may drop.

This refers to the uptime of the data centre, or the hosting providers that use the data centre.

What is uptime and the Uptime Institute?

Each data centre will have a different tier, based on some key factors. One of the more important ones (arguably the most important) is uptime. We’ll unpack the other factors as we go along.

Key point: In hosting, uptime is the amount of time a data centre stays operational.

That means the amount of time a data centre (in its entirety) can be running without going offline for any reason.

This tier classification system was created by the Uptime Institute. As you might’ve guessed from their name, their tiering list is centred around data centre uptime.

They created the international tiering standard for data centre performance, efficiency and reliability. They also provide unbiased and independent tier certification.

Their goal with the tiering system was to help shed light on data centre infrastructure. Knowing data centre specs means that businesses can decide on infrastructure that meets their specific needs.

An example would be government organisations that need to be available 24/7 using a Tier 4 data centre.

The different tiers of data centres

Like we mentioned earlier, there are four tiers that data centres can be classified into. The tiers are also progressive. That means the tier above incorporates the requirements of the tier below it.

This doesn’t necessarily mean that a Tier 4 is better than a Tier 2. Each of the tiers address different business operation requirements. Uptime Institute created a topology standard to show the criteria for each tier.

Looking at the topology, infrastructure and operational sustainability are the two essential components for classifying a data centre.

There are some other factors like building codes, regional weather, and property usage as well. These are things that data centre owners can look at from their own side, however.

So, with that out of the way, let’s get into the different tiers and their criteria. Our focus will be on Tier 3 specifically.

A table showing the different data centre tiers as specified by the Uptime Institute.

Tier 1 – Basic capacity

A Tier 1 data centre has the basic infrastructure to support the IT for general workspaces. The requirements are:

  • A UPS for power spikes, sags, and outages
  • An area for IT systems
  • Dedicated cooling equipment that keeps going after hours
  • An engine generator in case of power outages.
  • Twelve hours of fuel storage on site for power production

These are the basic requirements. Tier 1 data centres protect against human error, but not so much against unexpected outages.

The facility will also need to be shut down to perform maintenance tasks and other preventative activities. You can expect a maximum of 28.8 hours of downtime a year with a Tier 1 data centre.

Uptime: 99.671%

Tier 2 – Redundant capacity components

Tier 2 data centres offer a bit more in the way of redundancy components. These give the facility better maintenance opportunities with less chance for disruptions.

The requirements are:

  • Engine generators
  • Energy storage
  • Chillers
  • Cooling units
  • UPS modules
  • Pumps
  • Heat rejection equipment
  • Fuel tanks
  • Fuel cells

A Tier 2 data centre’s distribution path serves a critical environment. We can remove the site components without shutting down the system. Unexpected shutdowns, however, will still affect the facility.

Uptime: 99.741%

Tier 3 – Concurrently maintainable

With Tier 3 data centres, the name of the game is a concurrent maintainable site infrastructure. It has redundant capacity components and different independent distribution paths that serve the critical environment.

Tier 3 data centres only need one distribution path to serve the critical environment at any time. It has an expected uptime of 99.982%.

What separates Tier 3 from Tier 1 and 2 is that it doesn’t need to shut down for maintenance. Because the tiers are progressive, everything in the previous tiers gets added to the Tier 3 data centre.

A Tier 3 facility uses dual power IT equipment that needs a specific installation. This is to make it compatible with the site’s architecture. 

There’s also enough permanently installed capacity to meet the needs of the site when distribution paths are removed for any reason.

The site is not immune to outages, though. There are some operation errors and unplanned outages that may cause disruption.

For example, planned maintenance on the redundant components may cause an issue if there’s an unplanned outage as well.

Uptime: 99.982%

Tier 4 – Fault tolerant

Tier 4 is the highest at the moment. These data centres have several independent and physically isolated systems that can all serve as distribution paths. 

These sites can handle planned and unplanned outages. Like the Tier 3 sites, however, planned and unplanned outages together can increase the chance of disruption.

Tier 4 data centres don’t guarantee 100% uptime, but the redundancy makes it the closest we’ve come so far. The maximum downtime per year is 26.3 minutes. All the IT equipment must have fault-tolerant power designs to be compatible. That, alongside constant cooling makes the environment the most stable.

Uptime: 99.995%

Benefits of Tier 3 data centre

A chart showing the downtime experienced by Tier 3 data centres per year along with a zoomed in aspect to help visualize the percentage of downtime.

Now that we have an idea of the basic requirements for each tier, let’s go over some of the benefits of Tier 3 data centres.


Tier 3 data centres need N+1 redundancy at the least to be considered for this level. Let’s break down what this means.

Important note: N refers to the minimum capacity needed to operate a data centre at full load. If a data centre needs five generators to run at full capacity, N would be equal to five.

So, N+1 means the minimum load is present, plus one extra redundancy component. This separates Tier 3 from Tiers 1 and 2 since neither of the lower tiers have a full redundancy component.

They may have partial power and cooling redundancy, but not enough to replace a key power source in the event of an outage.

Having a redundancy system in place means an uninterrupted path for power to the data centre. That means uninterrupted service for you. 


With great power comes great reliability. Like we said earlier, Tier 3 uptime is 99.982%. That amounts to less than 1.6 hours of downtime annually. The redundancy components also mean maintenance won’t interrupt your service.

In essence, minimal unplanned downtime per annum. The usual customers for this level of reliability are large and growing businesses.

Maintenance flexibility

The selling point of Tier 3 data centres is the concurrent maintainability. Being able to perform security, health, and operational maintenance on the infrastructure without it disrupting operations is a big draw.

A simple example to drive this home would be working on your desktop or laptop while running system updates. Generally, you’d need to restart, or close certain programs to complete maintenance.

Tier 3 data centres make that a thing of the past.

Cost efficiency

Related to maintenance flexibility, cost efficiency also plays into the downtime reduction.

Any business with high traffic knows that time is money. Precious seconds or minutes with an offline website means revenue lost. A Siemens report highlighted some of the losses related to downtime.

An hour of downtime can average at R746,000 for certain sectors, while going all the way up to R38 million for others.

A bar graph showing the cost associated with downtime in different industries.

Businesses that need constant uptime for mission critical workloads shouldn’t consider anything below Tier 3 data centres. Naturally, staying online for longer (especially when your competitors aren’t) means an increased revenue over time.


As you’ve seen in this post, the benefit of Tier 3 data centres really begins to show when looking at uptime. The decrease in downtime is exponential, moving from less than 22 hours for Tier 2, to less than 1.6 hours for Tier 3.

If money makes the world go round, any savvy business owner would do well to keep it spinning by limiting downtime. The long-term advantages pay for themselves over time.

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