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.
With a tool such as FAST or Automatic Data Relocation, most of that effort is saved.
"The front-runner of those choices seems to be automated data movement," Forrester's Reichman said. It's crucial because it will let the average enterprise achieve the efficiency and savings they are after with flash, he said. In fact, he believes the wait for more automation software is holding back demand for flash storage.
"Auto tiering is the way to go," said analyst Henry Baltazar of The 451 Group. "It's too much of a pain to micromanage all those different workloads." He believes applications themselves will eventually do much of the work of assigning data to different tiers, but first there need to be standards across the industry so they can talk to different vendors' infrastructure, he said. The Storage Networking Industry Association is one organization working toward such standards. For now, it's up to individual vendors, he said.
In any automatic system, sub-LUN capability will be crucial, the analysts said. Because SSDs are much more expensive than HDDs, per bit, it makes no sense to store an entire database on flash just because some of it is frequently accessed.
"Putting a whole LUN on an SSD means that you really have the likelihood of wasting it," Reichman said. "It still is a 10X cost differential."