It's been more than five years since the unveiling of the Sun Blackbox, the first commercial data center container. Modular designs are now common in huge cloud data centers and high-performance computing (HPC), and vendors say they are poised to push further into the mainstream.

What's the state of the modular market? Five years in, the questions abound: Are any customers really buying them? Who are they? How large is the potential market? What does the analyst community think about modular data centers?

Here's an update in which we answer these questions.

Who Are the Companies Using Modular Data Centers?

Running servers in shipping containers was initially viewed as a niche play by many in the data center industry, limited to mobile requirements, temporary capacity, or novel designs like cloud computing facilities. Analysts and industry watchers have debated whether the efficiencies of modular data centers would be embraced by enterprise users, who are sometimes slow to adopt new technology.

Here's a look at IO isn't alone in public announcements of modular customers:

How Large is the Modular Market, and the Potential Market?

One of the challenges in assessing the uptake of modular data centers has been the lack of customers that will publicly acknowledge their use. One presumed explanation is that the earliest adopters were the U.S. military and other organizations that simply don't talk about their data centers.

There's one analyst number out there: In discussing demand for modular data center, HP noted a projection by IDC analyst Michelle Bailey that modular deployments will rise from 144 units this year to about 220 units in 2012.

How about the potential market? An August 2011 survey of Data Center Knowledge readers found that 35 percent are currently either using modular products or evaluating them with an eye towards adopting the technology in the next 12 to 24 months. Here's how it broke down:

Implementing modular data centers broadly: 7 percent

Implementing selectively: 10 percent

Modular data centers in testing and development: 7 percent

Planning to implement in next 12 months: 3 percent

Planning to implement in 12-24 months: 7 percent

No plans for modular data centers: 65 percent

That data suggests that these new designs aren't going to put traditional brick-and-mortar data centers out of business anytime soon, with two-thirds of the market unlikely to consider modular data centers in the short term. But it also shows that there will soon be a meaningful number of companies using modular designs. If they perform as billed and deliver savings, the appeal of modular construction may grow over time.

What does the analyst community think about modular data centers?

The economics of modular data centers vs. brick-and-mortar facilities is debated within the data center industry. Some in the industry believe enterprise customers will always want raised-floor environments inside hardened structures. What's undeniable is that the economic downturn and corporate belt-tightening has prompted many data center operators to consider new approaches. The beneficiaries of this trend include turn-key wholesale data centers, cloud computing providers and modular data centers.

“Today’s data center is obsolete when taking modularity and the fast maturation of this market into consideration,” said Jason Schafer, research manager at Tier1 Research. “If data center owners and operators are not at least exploring and considering modular components as a means for data center expansions and new builds, they are putting themselves at a significant disadvantage from a scalability, cost and possibly maintenance standpoint.”

Tier 1 was initially skeptical of modular designs. But it's not alone among leading analyst firms in believing that modular designs have a place at the table. David Cappuccio, chief of research for the Infrastructure team at Gartner, discussed the growing appeal of modular designs.

“When planning for data center growth, it is important that all alternatives be reviewed,” Cappuccio said last year. "Newer modular design techniques and container-based solutions should be a critical piece of your analysis. When used appropriately, they can solve specific problems, while reducing capital costs and the time it takes to implement new capacity.”

Modular designs will be a focal point for the 2012 Uptime Symposium this May. Last year the Uptime Institute's Professional Services unit hired a veteran of HP's modular program, Debbie Seidman, as its new Director of Technical Services. She will be managing Uptime Institute’s delivery of Design and Facility Tier Certifications worldwide.

“I don’t think we’ll see the entire data center market going modular," Seidman said. “It’s adaptable, compact, and can be less expensive in upfront costs. But you can’t just plug these things in, you need to ensure the infrastructure is in place.”

For a deeper dive into the modular market, check out the DCK Guide to Modular Data Centers, in which John Rath examines the different approaches to modular design, provides some definitions, and looks at the players in this emerging market.