Tagsbigtable, column-oriented, disk persistence, live server addition, NoSQL, open source, partitioning, rebalancing, replication, REST interface
HBase is the Hadoop database. Use it when you need random, realtime read/write access to your Big Data. This project's goal is the hosting of very large tables -- billions of rows X millions of columns -- atop clusters of commodity hardware. Hbase is an Apache Foundation project.