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 …