It’s been approximately a quarter of a century since the day when Uptime Institute LLC offered its innovative Tier Classification System. The said system is regarded by the majority of specialists as the world standard intended for assessing the important characteristics of data centers.
These days the above-mentioned classification is actively applied in a broad spectrum of segments inside the corresponding industry, from small-sized enterprises to influential hyperscale cloud providers. It assists both suppliers and customers in determining the prospective or foreseeable availability and failure survival as neatly as possible. It’s quite obvious that all technicians must know what data center tiers are like.
What Is the Tier-Based Classification of Data Centers?Â
The classification under consideration is a proven system created in 2005. It is aimed at evaluating data centers with respect to such parameters as redundancy, ease of maintenance, accessibility, and forecast non-failure operating time.
There are 4 official tiers, that is, from I to IV. Each level imposes certain requirements pertaining to electrical energy, cool-down, and failover capacity. One of the tangible benefits of this method lies in the fact that it helps professionals evaluate the data centers that are capable of withstanding a wide array of failures. On top of that, it provides the opportunity to find out whether one can service such data centers.
Companies that have to deal with humongous workloads on a regular basis tend to invest their funds in higher data center redundancy tiers in order to ensure strong failover protection and flawless data disaster recovery.
Tier 0
This sublevel isn’t actually included in the official classification. Nonetheless, it is commonly used within the industry anyway. It designates the server rooms or objects that don’t possess the proper redundancy systems, monitoring, or corporate infrastructure.
The said objects cannot effectively safeguard enterprises against downtime. Hence, they are deployed by the personnel working in small-sized firms that cannot allocate large amounts of money for maintaining their IT setups.
Tier 1
This is a very basic or generic level. It has separate channels for power supply and cool-down, along with uninterruptible power systems safeguarding the environment against outages and spikes. Still, these data centers aren’t fitted with the redundancy option. That’s why you won’t be protected in case one or several critical components in your setup become faulty.
What’s more, to maintain such systems, one has to fully de-energize them, i.e., to power them off. The worst thing is the fact that it can increase the risks of downtime, but a tier 0 data center is the most affordable solution compared to other options.
In this case, the projected uptime is equal to 99.671%, i.e., almost a day and a half, of downtime per year. Thus, a certain organization might lose its potential profits because of that. Even 1 hour of downtime can cost your company several million dollars. Consequently, this type is suitable mostly for enterprises that consider it acceptable to take hiatuses between the maintenance procedures.
Tier 2
This type is capable of ensuring partial redundancy. In addition, it guarantees higher accessibility compared to Tier 1. It also has standby generators, cooling systems, and power supply sources functioning in an N+1 configuration.
The uptime is 99.741%. This particular level requires high-quality maintenance from time to time in observance of certain rules, but it is better at tolerating a vast variety of faults in its components. This solution is intended mostly for deployment by medium-sized organizations, as they can provide higher robustness.
Tier 3
This type of data center supports real-time, simultaneous servicing. Hence, one can unplug or disable specific IT components without disrupting the operation of the system taken as a whole.
Such data centers feature a powerful redundancy option in an N+1 configuration and have a number of power supply and cooling channels. It follows thence that any component of a given IT infrastructure can be temporarily taken offline without disrupting the overall performance. This solution ensures 99.982% of non-failure operating time.
Tier 3 data centers are frequently used by successful enterprises that place a premium on accessibility. If you manage to take into account tier 3 data center requirements, you’ll be able to reach a balance between reliability and financial viability while guaranteeing the most appropriate level of uptime. On top of that, a lot of organizations opt for a tier 3 data center architecture, as it boosts flexibility and scalability within complicated IT setups.
Tier 4
A tier four data center is officially regarded as the most powerful solution. It is capable of reducing the number of potential faults to a minimum. Furthermore, it is equipped with a full-fledged redundancy option (2N or 2N+1).
This type has built-in standby systems that can provide the best sustainability indices. Plus, it can operate without hiatuses, regardless of the presence of faults or servicing procedures being performed.
When an incident takes place, the redundant systems are automatically activated to prevent disruptions. Chances are high that you won’t even be able to notice that something went wrong with your system.
To get the most out of their server environment as far as fault tolerance is concerned, enterprises should adhere to tier 4 data center requirements, since they encompass 100% redundant power, effective cooling, and intelligent network systems.
The guaranteed uptime of such data centers is 99.995%. It’s much closer to the industry standard than any other previously mentioned tier. This solution is applied in the fields where employees are engaged in processing critical data, i.e., finance, healthcare, and the government sector.
Tier 5
This extra high level isn’t recognized in the official classification. However, it is occasionally used to designate the state-of-the-art features. It offers all the functions of Tier 4, along with additional aspects, e.g., carbon neutrality (net zero), advanced automation processes, AI monitoring, etc.
Such data centers also support renewable power sources and meet all the crucial international standards. Your system will be able to continue operating without a water supply. On top of that, this type of data center is capable of handling dangerous air pollutants and keeping a check on energy systems.
Therefore, tier 5 is perfectly suited for huge enterprises that need to ensure the highest fallback recovery imaginable and comply with the latest environmental policies.
Even though the term in question is used mostly for marketing purposes, its popularity increases with those who are trying to achieve the nearly seamless, maximum stability possible.
What Type of Reliability Is Best for You?
One has to make up their mind depending upon their business requirements, more specifically:
- The first two tiers are suited predominantly for testing environments, that is, small-sized organizations and even start-ups, because such companies are usually ready to face temporary downtime.
- Tier III is the best choice for a firm that gives pride of place to high accessibility and the ability to service the hardware without interrupting the operation of the entire system.
- Tier IV is indispensable for complex applications that require flawless performance. In this case, even a short-term downtime isn’t acceptable.
When planning your potential IT solution, you shouldn’t focus on the budget only. You also have to take into consideration such factors as the criticality level of your workloads, compliance requirements, and operational risks.
Bottom Line
Overall, the classification in question is a highly effective measure aimed at assisting various companies in differentiating between facilities in reliance upon such aspects as resilience, uptime, and fault tolerance. If you manage to understand the key differences between the tiers, you’ll be able to arrive at well-argued, balanced decisions with regard to your IT infrastructure.
Even though higher tiers guarantee more stability, they also involve substantial cash investments. That’s why you should strive to find the golden mean between accessibility, price, and your business requirements. Evaluate your priorities and, where necessary, consult with certified technical experts to choose the optimal tier.