I think Apache Cassandra DB is what you are looking for.

Apache: The Apache Cassandra database is the right choice when you need scalability and high availability without compromising performance. Linear scalability and proven fault-tolerance on commodity hardware or cloud infrastructure make it the perfect platform for mission-critical data. Cassandra's support for replicating across multiple datacenters is best-in-class, providing lower latency for your users and the peace of mind of knowing that you can survive regional outages.

http://cassandra.apache.org/

http://planetcassandra.org/getting-started-with-apache-cassa...