Cassandra is emerging as one of the most powerful Big Data stores. it is often seen as a replacement for RDBMS but nothing can be farther than truth. Cassandra is a No-SQL database designed to store Terabytes of data in memory and provide less-than-50-milliseconds response to SQL like queries. But this is possible, only if, we know where to use Cassandra and how to deploy it. Cassandra is also an essential accompaniment for many real-time analytics applications. Cassandra can be used as part of Java or .NET applications using a variety of readily available Drivers.