EMC is developing its own automated tiering system, FAST (Fully Automated Storage Tiering), which will go on sale later this year and gain sub-LUN parsing capability in the middle of next year. Compellent Technologies was a pioneer in automating data movement and already has a system with sub-LUN capability.

Enterprises have three main options for using flash, according to analyst Andrew Reichman of Forrester Research. Using it as cache is best suited to enterprises that depend on very fast performance, such as stock exchanges, he said. Basic prioritization is automatic, and most storage vendors also offer tools for "pinning" certain types of data to flash so it doesn't automatically get purged from the cache.

Other organizations may install SSDs for their storage arrays and seek out or write better analytical tools to identify the most appropriate files to put there, Reichman said. However, not many IT departments have the spare resources to do it on their own, he said.

"Storage environments are overworked and understaffed as it is, and the likelihood of adding more things to do is slim," he said.

One enterprise that believes it has the smarts to take that path is MySpace. The company is currently using flash as cache, because speed is of the essence on the media-oriented social-networking service, according to Richard Buckingham, vice president of technical operations at MySpace. But it might expand that to SSDs in the future. Buckingham said MySpace has the technical expertise in house to develop its own automated tiering software, while few other organizations do.