When Google faced the trouble of analyzing huge datasets, such as web access logs and the page rank of a website. They used to employ an algorithmic approach which used to take up a lot of time and had to be re-done for every problem. So to get rid of it all, they tasked their… Continue reading
Posts in "Hadoop"
Hadoop Distributed File System
The Hadoop Distributed File System (HDFS) was developed following the distributed file system design principles. Running on commodity hardware, HDFS is extremely fault-tolerant and robust, unlike any other distributed systems.
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
Hadoop vs RDBMS : Which one suits your needs?
The tech growth in the last decade has been so great that the things once considered inconceivable are now mainstream and the tasks too difficult that required a special skill set can now be completed by almost anyone. In the midst of it all, huge volumes of data are being produced every day, and, as… 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
Different modes of hadoop
Hadoop can be run in 3 different modes. Different modes of Hadoop are
SQLifying NoSQL – Are ORM tools relevant to NoSQL?
Introduction If you reached this page, it’s fair to assume that you must have worked on at least one relational database in your lifetime. They have been in use for a quarter of a century and are found in almost all business applications.