Namenode in Safemode

This post shows what is Safemode in Namenode and what are the configurations for the safemode. You will also see the commands available to enter and leave the safemode explicitly. When the Namenode is started it loads the file system state into memory initially from the fsimage and then apply…

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Fair Scheduler in YARN

This post talks about Fair Scheduler in Hadoop which is a pluggable scheduler provided in Hadoop framework. FairScheduler allows YARN applications to share resources in large clusters fairly. Table of contents Overview of Fair Scheduler in YARN Hierarchical queues support Configuration for Fair Scheduler Setting up queues Queue configuration example…

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Array in Java

In this post we’ll talk about one of the programming construct array in Java. Topics covered are how to declare an array, how to create and initialize an array, how to store elements in an array and how to access those elements using array indexes, types of arrays in Java.…

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