Today's databases are not only expected to be flexible enough to handle a variety of data formats, they're also expected to deliver extreme performance and to scale to handle humongous data volumes. The rise of the web as a platform also created a vital factor change in data storage as the need to support large volumes of data by running on clusters. Relational databases were not designed to run efficiently on clusters. The data storage needs of an ERP application are lot more different than the data storage needs of a Facebook or Twitter, for example. When considering performance, the determining factors in database choice are the underlying data formats and the number of operations being performed. This paper describes that the areas where and how NoSQL performed well over RDBMS as well as the use cases where different types of NoSQL databases can be used. Moreover it includes the improved architecture scenario and design aspects of NoSQL database.