No More Fears For Tiers

Data centres are increasingly described in terms of their Tier Rating. This widely used reference is the IP of the Uptime Institute (UI) and users of the terminology are advised to acknowledge and respect this fact at all times. Far too many businesses are not registered with the UI yet continue to make reference to and rely upon the Tier Rating system in their own internal assessments of their facilities. Many businesses quite blatantly claim their facilities are of a certain Tier Rating when they clearly are not. Some people call this misrepresentation - we call this mis-selling.

If you are in any doubt about the standard of the facility you are thinking of buying into, have an independent ACE member consulting firm carry out a technical audit or, better still, ask the UI for their own opinion. You will be shocked at how many of the smaller computer room-style ‘Data Centre’ firms cite Tier III as their standard yet most have never been asked to prove it; we firmly believe that most would fail any such technical audit.

For many IT businesses and organisations the Tier System meaning can initially sound complex and it can be difficult to understand the detail behind it. The UI consider many factors in their Tier Rating assessment and there is plenty of technical jargon involved; the understanding of Tier Ratings can be impenetrable to many non-technical people in our industry. With that in mind, Firstnet thought it might be useful to explain our interpretation of the Tier System and what it might mean to your organisation.

The UI created the Tier Classification System using standardised methodology to evaluate data centres in terms of their ability to maximise ‘uptime’ – in other words, the measure of the time that critical IT infrastructure (hardware, software, networks and related facilities/equipment) is working and available. Tier Ratings have become the global standard of assessment and most professional data centre owners and operators will turn to the UI for accreditation and certification of this unbiased benchmarking system.

There are four levels within the ratings system: Tiers I, II, III and IV. These Tier levels relate to the level of resilience in the engineering infrastructure that supports the IT function, commonly referred to as ‘redundancy’. In the context of data centres, an example of redundancy is a particular element being duplicated so that, should the primary resource fail, a backup is there to continue to deliver the service. Redundancy is installed for a wide range of critical features that could affect uptime in the event of component failure, including power sources, cooling equipment, network system components, hard disk drives, servers, operating systems, switches and telecommunication links.

The Tiers (I-IV) are progressively more complex and become less prone to failure with each step up in Tier rating.

The most basic data centres are Tier I. They provide a dedicated site infrastructure to support the IT function beyond an office setting. They have an uninterruptible power supply and dedicated cooling equipment that continues outside normal office hours. However, they offer little (if any) redundancy with a single path for power and cooling to the server equipment and no redundant plant. They are not equipped to promise any particular level of uptime.

Tier II data centres include more features to reduce vulnerability to unplanned downtime due to system failures. They offer partial redundancy with certain redundant components and backup elements – e.g. an additional cooling system and/or a generator – but they commonly have only a single path for both power and cooling.

Tier III data centres provide a more sophisticated infrastructure with greater levels of redundancy and higher levels of uptime. They must provide N+1 levels of fault tolerance, which essentially means that an independent power backup is in place for each system component in the event of its failure or removal from service due to maintenance. Tier III centres provide dual power sources for all IT equipment as well as concurrently maintainable power and cooling distribution paths to server equipment, so if one path fails, another can take the load, transparent to the IT function. They are designed to facilitate all faults, maintenance and upgrades on-site without causing downtime.

Tier IV date centres are designed to provide comprehensive redundancy with all system components being both concurrently maintainable and fully fault-tolerant. They have multiple cooling units, backup generators, power sources and chillers.

Operational complexities and infrastructure costs increase with each Tier Level, so when evaluating the level of service you need from a data centre, you need to determine the Tier Level that fits the scale and requirements of your organisation. The substantial difference in resilience between Tiers II and III has made Tier III a minimum sought-after certification for the majority of SME customers, valued by data centre owners and customers alike. However, achieving Tier III requires substantive expertise and investment from the owners: Firstnet’s purpose-built data centre will soon be classified as one of the very few genuine Tier III colocation facilities in the north of England.

Tier III offers an ideal service level for many corporations, but we are also attracting a high volume of enquiries from SMEs interested in maximising the benefits of Tier III. With plans in place for long-term growth, many of them value the flexibility that Firstnet’s data centre provides. Our facility offers custom colocation with cloud technology that makes your data, storage and networking systems completely scalable for your future needs. Everything can be upsized and/or upgraded as your company evolves; we offer our clients a completely future-proof IT resource.

The Firstnet data centre offers enhanced levels of physical security as well as a workplace recovery suite on the same site, so in the event of a fire or other disaster, you can drop in and sit down at a workstation with instant access to your entire IT infrastructure.

If you’d like to know more about Firstnet’s data centre or Tier Ratings in general, please call us on 0330 041 5009. Alternatively, you can get in touch via email at

18th September 2017