Microsoft is gradually moving away from mechanical-disk storage and toward solid-state drives, starting with high-density storage applications, such as SAN. The company has started replacing spindles with speeds of 10,000RPM or faster in its data centers with SSD arrays, with plans to gradually make a total transition to SSD-based storage.

One of the main reasons is its transition to a new container-based data center design, which Microsoft manager of global operations engineering Nic Bustamante says is not very friendly with high-density storage systems comprised of mechanical disks.

"Search is number-one on our radar," Bustamante said about the transition to SSD. Because Microsoft is competing with Google in the search market, it is looking for any edge it can gain and using SSD-based storage to support the Bing search engine helps gain some of that edge.

Bustamante spoke at the DatacenterDynamics conference in Dallas Tuesday.

One of the reasons Microsoft’s ITPAC’s do not do very well with spinning media are high-density loads inside the modules. The capacity of cooling systems required for these loads creates an amount of vibration spindle-based media do not tolerate well, Bustamante said.

The second reason is connectivity. There is limited room for cabling within an ITPAC.

The third reason is the massive weight of mechanical-disk-based storage arrays, which drives up the cost of transporting the modules and "eating into" one of the main benefits of a modular design: low cost and high speed of deployment.

Finally, the fourth reason ITPAC’s do not like spinning media is their general preference for stateless applications and equipment that does not need to be replaced or serviced often. "You know that a mechanical disk is going to fail," Bustamante said. Access to equipment for maintenance may be difficult within a module;also, conditions within and around the module may not be too pleasant for people to work in.

While some parts of the company already have access to SSD-based storage, all property groups at Microsoft will be able to get SSD products for their systems beginning in the second half of 2011. The transition to SSD includes both data centers and employee PC’s and laptops.

While the cost of enterprise-quality SSD products may currently exceed traditional storage by 40-100%, Bustamante believes cost of the two technologies will be level in about two years from now.

Kevin Timmons, general manager at Microsoft Data Center Services, announced the company’s new modular data center design at the DatacenterDynamics conference in New York in March. The company currently has three data centers under construction that are using the design: Quincy, Washington, Boydton, Virginia, and Des Moines, Iowa.