Casssandra is an open source database system released under Apache.Cassandra is a highly scalable database system that can store and manage a very large amount of data. It can be used either as a real time operational data or a read insensitive database, as the former can be used in case of online transactional applications and the later can facilitate large scale BI systems. Cassandra deploys automatic data replication into multiple nodes for fault toleration. As each node which is replicated are completely identical, there is a minimal possibility for network bottlenecks.