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Data Center Tiers — the whole story on these key ratings

For an “apples to apples” comparison of data centers, data center tiers are a good place to start. Tier certifications make sure that data centers satisfy clear, comparable criteria. They help you choose the right data center to meet your goals.

Yet tier certification ratings alone only tell you part of the story. True, they let you compare expected uptime between data center facilities. However, availability is only one piece of the puzzle. You also need to know how to align ratings with different types of business.

In this article, we describe tier classification levels. We position them for different needs. As well as telling you what they can do, we also tell you what they cannot do. You get the whole story about the data center tier system and how to choose for your organization.

All about availability

Businesses rely more and more on their data and information systems. Data center availability is a key factor. The time you can survive without your data or systems depends on your type of business. For some, an outage of days or hours might be tenable. For others, even minutes of downtime could be a disaster. Many businesses therefore look to data center operators for uptime guarantees.

But what sort of uptime promise can you get? How can you compare one specification with another? Enter data center tier classification. Using open or industry standard criteria, an independent entity can assess and rate data centers. A data center can then present its rating to users to set their expectations.

An example of such an entity is the Uptime Institute. It has defined its own data center classifications that are divided into four levels or tiers. The tiers define criteria for maintenance, power, cooling, and fault handling. Each tier builds on the tier below, adding stricter criteria. An example of an open standard is ANSI/TIA-924-B. There are similarities between this standard and the Uptime Institute criteria.

Getting certification for a data center can be expensive. This is especially true for higher tiers like Uptime Institute Tier III and Tier IV. Some data centers may simply declare that their facilities have uptime to the same level as a certain tier. For example, “Tier III equivalent”. However, if no official rating exists, users should check for themselves.

Data Center Tiers I to V

The main differences between data center tiers are in uptime, redundancy, and paths for power. For data center operators, added factors are costs and times to implement. Each tier rating is based on the weakest component or system in the data center. The higher the availability required, the higher the cost of the data center facility.

The Uptime Institute tiers for data centers can be summarized as follows.

Tier I

A Tier I data center has an area for IT systems with dedicated cooling. It has an uninterruptable power supply (UPS). It also has an engine generator for power outages. Tier I protects against human error. It does not protect against unexpected failure or downtime. The facility must shut down for maintenance and repairs.

Tier II

A Tier II data center includes Tier I capabilities. It adds redundant power and cooling at the component level. This improves protection against disruptions. Maintenance of components can be done without an entire shutdown. However, failures will affect the system.

Tier III

A Tier III data center builds on Tier II capabilities. It adds distribution path redundancy to the Tier II component redundancy. No shutdowns are needed for maintenance or replacement of equipment. Any part can be shut down without impact on IT operations.

Tier IV

A Tier IV data center adds fault tolerance to the Tier III capabilities. Redundancy comes from independent and physically isolated systems. There will be no disruption from planned or unplanned events. However, if maintenance is in progress, a failure may mean a higher risk of disruption.

Tier V

There is also a Tier V. It has been defined by the service provider Switch. Tier V aims to enhance uptime and reliability for colocation facilities. Tier V data centers must meet all the Tier IV conditions plus other even stricter ones.

Which tier rating is right for my business?

How do tier certification ratings relate to the real world? There are no hard and fast rules. However, the following indications may help.

Tier I

  • Smaller businesses, branch offices.
  • Bricks and mortar businesses or those with a limited online presence.
  • Low reliance on IT like professional service or construction firms.
  • Downtime is unwanted but not a disaster.

Tier II

  • Dependent on phone systems and/or email, like support centers.
  • Use of multiple servers.
  • Physical points of sale, customer relationship management (CRM).
  • Limited, scheduled downtime can be handled.

Tier III

  • Highly dependent on IT and or VoIP phone system.
  • Online business is the biggest source of income.
  • High profile brand, nationwide (worldwide) presence.
  • Enterprise resource planning (ERP), insurance, hospitals, online banking.

Tier IV

  • Multimillion dollar organizations.
  • Critically dependent on IT and/or electronic transactions.
  • Downtime costs are high.
  • Financial securities trading, electronic funds transfer, energy utilities.

Moving from one tier to another means more investment by data center operators. In turn, data center and colocation prices go up for customers. For example, a Tier IV data center may cost twice as much to build as a Tier III data center. Many customers opt for Tier III as a good mix of availability and affordability.

How many nines do you need?

Each of the four data center tiers corresponds to a certain minimum uptime. Or in other words, a certain maximum downtime.

  • Tier I (basic) is 99.671% uptime. This is “two nines” or better. Annual downtime is then 28.8 hours.
  • Tier II (redundant components) is 99.741% uptime. Again, this is “two nines” or better. Annual downtime is 22.0 hours.
  • Tier III (concurrently maintainable) is 99.982% uptime. This is “three nines” or better. Annual downtime is 1.6 hours.
  • Tier IV (fault tolerant) is 99.995% uptime. This is “four nines” or better. Annual downtime is 0.4 hours.

To see how many “nines” you need, start by estimating the cost of downtime to your business. Cost may be financial, as in loss of revenue. However, downtime can also cost you in terms of your reputation. For some organizations, there may be fines for non-compliance. Overall, higher costs of downtime will mean more “nines”.

More uses for data center tier ratings

An operator can use tier standards to drive design of its data center. It is better to include availability while building a facility. Trying to bolt on availability after is harder and riskier. Whichever approach is used, an assessment by a recognized entity is still needed for a rating.

Businesses using data center services can show the rating to their own market. Your clients and partners may even insist on such proof. They want to know that they are not at risk because of a problem with your uptime. Likewise, your stakeholders want to see that you are protecting their investments.

Dealing with collateral impacts

Data center availability costs more than money. It also has an ecological impact. Businesses are under pressure to make their carbon footprint smaller. Stakeholders and governments want to see results. Carbon footprints also extend to partners and suppliers. Businesses cannot pass the buck to their providers. They must be sure that the raw materials and services they use are green as well.

Data centers should strive to be as efficient and as green as possible for a given data center tier certification. Users also need a green approach. Right-sizing of uptime is key. Poor availability can hurt business. On the other hand, uptime specifications that are too high are wasteful.

The Uptime Institute encourages effective and efficient operations. However, its focus is on behaviors and risks in data centers. It is not on carbon footprints. The Tier V standard from Switch is greener. It demands that data centers run on local, renewable energy.

Overall, good design decisions help make data centers and their availability green. Sustainability can rise via the following choices.

  • Efficient cooling air distribution, heat removal, and water saving. This cuts down on waste.
  • Smaller carbon footprint of power generators.
  • High density racks for lower overall power and cooling needs.
  • Better power usage effectiveness (PUE). A lower PUE is more efficient and economical.

SpaceDC builds data centers that are sustainable as well as available. Our company focuses on the low-carbon factors listed. At the same time, we achieve Uptime Institute rating certifications for our data centers internationally.

What tier ratings do not do

Tier ratings help to compare data center uptimes. However, they do not cover all uptime factors. Local geography and weather are examples. So are security, staffing, and compute infrastructure. These items can also affect availability over the short or long term. So, while making the most of tier certifications, it also pays to check the following.

  • Protection against natural disasters. Regional storms and floods are classic cases. Check that the data center you want to use is properly disaster proofed.
  • Security at multiple levels to prevent breaches and downtime. Staff to deal immediately with any incidents. Industry threat and vulnerability risk assessment (TVRA) standards apply. Security should meet these standards as a minimum.
  • Expert onsite support to help customers with uptime related tasks. These include IT asset deliveries, installs, compliance, updates, and audits.
  • Hardware technology, flexibility, and innovation. These help to meet new compute demands quickly and efficiently with the right uptime.
  • The right data center availability for you today must also be the right one for you tomorrow. SpaceDC ensures that its data centers continually conform to all the uptime requirements listed above.

Official data center tier ratings help you to see what uptime you can expect from a data center, and therefore, which data center tier certification best suits your business. The estimated cost of downtime to your organization will steer you towards a suitable tier. Finally, be sure to consider any additional factors for a well-rounded view and the right data center choice.

Contact us if you would like to find out more about how SpaceDC can help your organization to achieve optimal data and systems uptime.

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