'Big Data 'describes and technologies to store, distribute, manage and analyze large-sized datasets with high-velocity. Big data can be structured, unstructured or semi-structured, resulting in incapability of conventional data management methods. Data is generated from various different sources and can arrive in the system at various rates. In order to process these large amounts of data in an inexpensive and efficient way, parallelism is used. Hadoop is the core platform for structuring Big Data, and solves the problem of making it useful for analytics purposes. Hadoop is an open-source software project that enables the distributed processing of large data sets with a very high degree of fault tolerance.