Hadoop HDFS and MapReduce Core Concepts Explained

Posted by on Jul 2, 2025 in Information Technologies Engineering | 0 comments

HDFS NameNode vs. DataNode Differences

  • NameNode is the master node in HDFS, while DataNode is the slave node.
  • NameNode stores metadata like file names, directory structure, permissions, etc.
  • DataNode stores the actual data blocks of the files.
  • NameNode manages the namespace and regulates access to files.
  • DataNode performs read and write operations on HDFS blocks.
  • There is only one active NameNode (with a standby for high availability).
  • There are usually many DataNodes in a Hadoop cluster.
  • If NameNode fails,
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