Microsoft's plan to fill its mammoth Chicago data center with servers housed in 40-foot shipping containers has experts wondering whether the strategy will succeed. In Microsoft's plan, each container in the data center, still being built, will be filled with several thousand servers.

Several outside experts were queried -- including the president of a data center construction firm, a data center engineer-turned-CIO, an operations executive for a data center operator and a "green" data center consultant -- to get their assessments of the strategy. While they were individually impressed with some parts of Microsoft's plan, they also expressed skepticism that the idea will work in the long term.

Here are some of their objections, along with the responses of Mike Manos, Microsoft's senior director of data center services. Manos spoke in an interview after the Data Center World show at which Microsoft's plan was announced.

1. Russian-doll-like nesting (servers, on racks, inside shipping containers) may work out to less Lego-style modularity, as some proponents claim, and more mere ... moreness

Server-filled containers are "nothing more than a bucket of power with a certain amount of CPU capacity," quipped Manos.

His point is that setting up several thousand servers inside a container in some off-site factory setting will make them nearly plug-and-play once the container arrives at the data center. By shifting the setup to the server vendor or system integrator and then wrapping it up inside a 40-foot metal box, containers become far easier and faster to deploy than individual server racks, which have to be moved one at a time.

But people like Peter Baker, vice president for information systems and IT at Emcor Facilities Services, argue that in other ways, containers still "add complexity."

"This is simply building infrastructure on top of infrastructure," he said.

One example, says Baker -- who worked for many years as an electrical engineer building power systems for data centers before shifting over to IT management -- is in the area of power management. Each container, he says, will need to come with some sort of UPS (uninterruptible power supply) that does three things: 1) converts the incoming high-voltage into lower usable DC voltages; 2) cleans up the power to prevent it from spiking and damaging the servers; 3) provides backup power in case of an outage.

The problem is that each UPS, in the process of "conditioning" the power, also creates "harmonics" that bounce back up the supply line and can "crap up power for everyone else," Baker said.

Harmonics is a well-known issue that's been managed in other contexts, so Baker isn't saying the problem is unsolvable. But, he argues, the extra infrastructure needed to alleviate the harmonics generated by 220 UPSs -- the number of containers Microsoft thinks it can fit inside the Chicago data center -- could easily negate the potential ROI from using containers.

Manos' rebuttal: "The harmonics challenges have long been solved [by Microsoft's] very smart electrical and mechanical folks," he said, though he declined to go into specifics. Manos added that he also "challenged the assumption" that Microsoft's solutions are bulky and non-cost-effective: "You can be certain that we have explored ROI and costs on this size of investment." He also admonished critics' speculation that relies too heavily on the "traditional way of thinking about data centers," again, without going into detail.