Facebook: “There are no published cases of NoSQL databases operating at the scale of Facebook’s MySQL database.”

From a recent GigaOM report.  So if Facebook doesn’t need NoSQL, who does?

Callaghan was more open to using NoSQL databases, but said they’re still not quite ready for primetime, especially for mission-critical workloads such as Facebook’s user database. The implementations just aren’t as mature, he said, and there are no published cases of NoSQL databases operating at the scale of Facebook’s MySQL database. And, Callaghan noted, the HBase engineering team at Facebook is quite a bit larger than the MySQL engineering team, suggesting that tuning HBase to meet Facebook’s needs is more resource-intensive process than is tuning MySQL at this point.

Facebook shares some secrets on making MySQL scale — Cloud Computing News