Introduction to No SQL databases for Big Data

With the advent of Big Data, we need Databases that are highly scalable and can handle large volumes of structured and unstructured data. Traditional RDBMS are not suitable for this. A new breed of Databases called NoSQL databses are gaining momentum in this space.
NoSQL stands of Not Only SQL. There are different types of NoSQL databases like Key Value Pair, Document type, Columnar etc. Each of these types are best suited for a specific type of application. Most of these databases like HBase and Cassandra are available as open source. And there are commercial versions of the same also available. For example Datastax is a commercial distribution of Cassandra.