Hadoop Interview Questions and Answers

41.What does “file could only be replicated to 0 nodes, instead of 1” mean? The namenode does not have any available DataNodes.

31.Default replication factor to a file is 3. Use ‘-setrep’ command to change replication factor of a file to 2. hadoop fs -setrep -w 2 apache_hadoop/sample.txt

21.What is a ‘block’ in HDFS? A ‘block’ is the minimum amount of data that can be read or written. In HDFS, the default block size is 64 MB as…

11.What is Fault Tolerance? Suppose you have a file stored in a system, and due to some technical problem that file gets destroyed. Then there is no chance of getting…

1.What does ‘jps’ command do? It gives the status of the deamons which run Hadoop cluster. It gives the output mentioning the status of namenode, datanode , secondary namenode, Jobtracker…