Comment hbase is an option to NoSQL and Cassandra. (Score 3, Informative) 222
I recently read that someone moved their large operation from Cassandra to Hbase, a hadoop file system. http://hbase.apache.org/
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 open-source, distributed, versioned, column-oriented store modeled after Google' Bigtable: A Distributed Storage System for Structured Data by Chang et al. Just as Bigtable leverages the distributed data storage provided by the Google File System, HBase provides Bigtable-like capabilities on top of Hadoop. HBase includes:
Convenient base classes for backing Hadoop MapReduce jobs with HBase tables
Query predicate push down via server side scan and get filters
Optimizations for real time queries
A high performance Thrift gateway
A REST-ful Web service gateway that supports XML, Protobuf, and binary data encoding options
Cascading, hive, and pig source and sink modules
Extensible jruby-based (JIRB) shell
Support for exporting metrics via the Hadoop metrics subsystem to files or Ganglia; or via JMX
HBase 0.20 has greatly improved on its predecessors:
No HBase single point of failure
Rolling restart for configuration changes and minor upgrades
Random access performance on par with open source relational databases such as MySQL