Name: Cassandra
Website: www.cassandra.apache.org
Description:

The Apache Cassandra project is the best-in-class when it comes to support for replicating across multiple data centers to make you survive regional outages; thus, it provides lower user latency and peace of mind.

Offering a platform with linear scalability and proven fault-tolerance on commodity hardware or cloud infrastructure, Apache Cassandra database is the perfect choice when considering high availability of your mission-critical data without compromising performance.

With Cassandra, there are no sing points of failure, no network bottlenecks, and every node in the cluster is identical.

Users have control in choosing between synchronous or asynchronous replication for each update, and replication across multiple data centers is supported. Companies like eBay, Twitter, Reddit, Cisco, and Digg utilize Apache Cassandra.