Architecture of HDFS is very strong in nature. HDFS has a
unitary NameNode. Main severs holds the responsibility of
managing file systems namespace and also manages file
access controlled as per client requests. The number of
Multiple DataNodes, usually one per node resides in the
cluster. Data is stored in files in HDFS. The file is then split
into number of blocks and these blocks are stored in sets of
DataNodes. NameNode does the execution of different
operations of file system namespace. NamNode maps the
blocks of data on DataNodes. File System Clients Requests
are handled by the DataNodes. Instructions from NameNode
for Creation Deletion and Replication of data block are also
performed by DataNodes.