Aster Data Systems, which stores data for social networking site MySpace (and others), has raised $12 million in a second round of venture funding.

The Redwood City, Calif. startup offers “frontline data warehousing,” which basically means storage of all of a company’s data for business analysis. Aster dubbed its system nCluster because the data is spread across clusters of cheap servers. The company says nCluster offers three key innovations compared to competitors like Teradata, Netazza and DATAllegro: It can run on relatively cheap hardware; it uses the MapReduce programming framework popularized by Google, allowing for more detailed queries of the data; and it’s “always on,” without planned or unplanned downtime.

It may be hard to judge Aster’s claims on their own, but the list of high-profile customers and backers lends a lot of credibility. MySpace, for example, uses nCluster to store and analyze all of its traffic data, which adds up to more than 100 terabytes of data spread over clusters of more than 100 servers. Aster says its customers now number in the double digits and that it’s bringing in “multi-million dollars” in revenue. With the downturn, it’s taking longer to convince nCluster customers to buy, but Aster says it’s still a tempting purchase because it helps companies avoid buying expensive hardware, and because it can be deployed relatively quickly.

The current round was led by JAFCO Ventures, which also invested in DATAllegro. Existing investors Sequoia Capital, Cambrian Ventures and First Round Capital also participated. Aster has raised a total of $22 million to date. Angel backers included David Cheriton, Rajeev Motwani and Ron Conway, who were all early Google investors and advisers.