In Hadoop MapReduce, shuffling is used to transfer data from the mappers to the important reducers. It is the process in which the system sorts the unstructured data and transfers the output of the map as an input to the reducer. It is a significant process for reducers. Otherwise, they would not accept any information. Moreover, since this process can begin even before the map phase is completed, it helps to save time and complete the process in a lesser amount of time.