Posts in "Hadoop"

Hadoop Architecture

Apache Hadoop is a java based open source software. Basically, it’s a framework which is used to execute batch processing jobs on huge clusters. It is designed so that it can be scaled from a single server to hundreds of thousands of nodes in the cluster, with a high extent of fault-tolerance. Rather than relying… Continue reading

Format aborted in /app/hadoop/tmp/dfs/name

While startng the Hadoop i was just trying to format the filesystem. For that i have executed below command. bin/hadoop namenode -format But i am getting below error while doing this. Could you please let me know what could be the reason behind this. Warning: $HADOOP_HOME is deprecated. 13/08/10 13:52:56 INFO namenode.NameNode: STARTUP_MSG: /************************************************************ STARTUP_MSG:… Continue reading

Hadoop Interview Question

What is the difference between start-all.sh and start-dfs.sh in Hadoop   There are different scripts in bin dir in Hadoop which is used to launch Hadoop DFS and Hadoop Map/Reduce Daemons. start-dfs.sh – Starts the Hadoop DFS daemons (Namenode and Datanodes) stop-dfs.sh – Stops the Hadoop DFS daemons (Namenode and Datanodes) start-all.sh – Starts all Hadoop daemons (Namenode, datanodes,… Continue reading