Tuning Datanode

In this recipe, we will look at tuning the Datanode by making some important configuration changes. Datanodes are mostly I/O bound, but can have a varied workload for HBase region servers. The network throughout the disks must be tuned for optimal performance.

We will look at parameters only for the Datanode, which in production will come into effect in conjunction with HDFS and Namenode parameters, discussed earlier in this chapter.

Getting ready

For this recipe, you will again need a running cluster and have at least the HDFS daemons running in the cluster.

How to do it...

1. Connect to the master node master1.cyrus.com and switch to user hadoop.

2. The hdfs-site.xml file will remain the same in the cluster. Each of the Namenode and Datanode daemons will read its respective parameters, ignoring the others.

3. Tune the Datanode handler count by using the following configuration in the hdfs-site.xml file:

   <property>
   <name>dfs.datanode.handler.count</name>
   <value>40...