Question - What is MapReduce?
Answer -
MapReduce is a software framework in Hadoop that's used for processing large data sets across a cluster of computers in which each node includes its own storage. MapReduce can process data in parallel on these nodes, making it possible to distribute input data and collate the results. In this way, Hadoop can run jobs split across a massive number of servers. MapReduce also provides its own level of fault tolerance, with each node periodically reporting its status to a primary node. In addition, MapReduce offers native support for writing Java applications, although you can also write MapReduce applications in other programming languages.