In order to solve this, we move processing unit to data instead of moving data to processing unit. So, what does it mean by moving the computation unit to data? It means that instead of moving data from different nodes to a single master node for processing, the processing logic is sent to the nodes where data is stored so as that each node can process a part of data in parallel. http://webtrackker.com/Best-hadoop-training-institute-center-in-noida-sector-15-16-18.php