MySQL AB, developer of the world's most popular open source database, today launched MySQL Cluster, a new open source database clustering technology for applications requiring continuous availability. MySQL Cluster combines the MySQL® database with a clustering architecture to deliver 99.999 percent availability to mission-critical database applications. It is the first affordable, enterprise-scale database clustering software.
This is very cool! Five 9s reliability in an open source database. Great for those "mission-critical" hobbies =) It looks like its released under a dual license, one open source and one commercial license for software vendors and commercial MySQL customers.
Full press release here.
MySQL Cluster FAQ