Digital Realty, Uptime Debate Tier System

What tier is your data center? Most of you know the answer, or at least are familiar with the question. The tier system developed by The Uptime Institute for classifying different levels of data center reliability has become central to discussions of how to plan and design enterprise data centers. Uptime refers to it as the "de facto industry standard for predicting site reliability." But the four-tier rating system also has its critics, and a recent critique from Digital Realty Trust (DLR) has prompted a public response from the Uptime Institute.

In a recent video, Digital Realty Trust executive vice president Michael Manos discussed "The Myth of Tiers," saying that tier definitions have assumed an oversize role in data center design discussions.

"Uptime stepped up and defined the language with which the industry could talk about redundancy and resiliency," Manos said. "For a long time, that has proven to be very successful. ... The challenge today is that data center industry is entering a time of real dynamism in terms of the design approach.

Dogmatic Adherence? Or Misusing Tiers?

"What I've seen in the industry is this dogmatic adherence to these uptime tiers (in which) they're really not taking into consideration their own real needs," Manos continued. "They're defaulting into a Tier II or Tier III or Tier IV because over the course of the last 10 to 15 years, this standardization of how we talk about the industry has been really driven into the fore of how people think about it. In many cases, I see the Uptime tiering methodology being used as a crutch by those folks not willing to do the investigation internally to find out what their actual needs are."

In its response, The Uptime Institute said those companies are not really following the tier system in the first place. "The tiers are predicated on the business case of the individual company," Uptime wrote. "Without determination of a unique business case, organizations are misusing the Tiers and bypassing the internal dialogue that needs to occur."

Manos also argued that implementation of best practices could eliminate the need to invest in the redundant equipment and systems required to meet Tier IV standards. "You can have a Tier II facility with very strong, rigorous organizational best practices in place ... and achieve the same level of uptime as Tier IV facility," Manos said. "If you operate your data center the correct way, you can run your facility in a Tier IV operating range at a much cheaper overall ownership cost than just building a Tier IV data center."

Uptime disagrees. "Many owners' business cases require Tier IV, including banking/financial; insurance; outsourcers in UK, Middle East, and South Africa; and federal and provincial governments," it wrote. "Tier IV is not the best answer for all organizations, neither is Tier II."

Concurrent Maintainability

A key discussion point was concurrent maintainability - the ability to perform maintenance without taking the data center offline.   

"Tier II ensures redundant capacity components, but requires a shutdown of the computer room for planned maintenance or replacement of critical equipment," Uptime wrote. "Mr. Manos mentions Tier II and IV solutions, but disregards Tier III. The requirement to maintain infrastructure without shutting down equipment, known as Concurrent Maintainability, defines Tier III. Many owners' business cases, including healthcare, domestic outsourcers, and state governments, require Tier III."

While The Uptime Institute continues to make its case for the value of the tier system, it has also begun a process for end users to suggest adjustments to the tiers to address the changing environment.

Certification vs. Marketing

Manos' comments and Uptime's response both focus on a key challenge for the tier system. The tiers were developed by Uptime, which recently launched a suite of professional services and certifications for data center audits. But over the years, the "tier" concept has become almost industry shorthand for certain levels of infrastructure redundancy. 

A large number of facilities market themselves as being Tier III or Tier IV. But the full list of sites that have been certified by Uptime shows that only two data centers have received Tier IV certifications based on site inspections, while another 13 facilities (five completed, 8 under construction) have been certified based on designs.

Some data center operators, such as Virginia's OnePartner, continue to emphasize the importance of certification. Meanwhile, efforts to launch competing classification systems have gained limited traction. 

A key question going forward is whether critiques of the tier system contribute to Uptime's effort to keep the standard relevant, or fundamentally alter the conversation and prompt new language and framework for industry discussions of reliability.

What do you think? Share your thoughts in the comments.