HADOOP DISTRIBUTED FILE SYSTEM

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Introduction


Apache Hadoopis asoftware frameworkthat supports data-intensivedistributed applicationsunder afree license.It enables applications to work with thousands of nodes andpetabytesof data.
Hadoop was inspired byGoogle'sMapReduceandGoogle File System(GFS) papers.
Hadoop is a Apacheproject being built and used by a global community of contributors, using theJavaprogramming language.
Yahoo!has been the largest contributor to the project, and uses Hadoop extensively across its businesses.
Hadoop was created byDoug Cutting, who named it after his son's toy elephant.


Benefits of Hadoop


Hadoop is designed to run on cheap commodity hardware
It automatically handles data replication and node failure
It does the hard work –you can focus on processing data
Cost Saving and efficient and reliable data processing


Overall Architecture


A small Hadoop cluster will include a single master and multiple worker nodes.
The master node consists of:-
Jobtracker
Tasktracker
Namenode
Datanode.
A slave orworker nodeconsists of a datanodeand tasktracker, though it is possible to have data-only worker nodes, and compute-only worker nodes