Configuring HDFS block size

Getting ready

To step through the recipes in this chapter, make sure you have completed the recipes in Chapter 1, Hadoop Architecture and Deployment or at least understand the basic Hadoop cluster setup.

How to do it...

1. ssh to the master node, which is Namenode, and navigate to the directory where Hadoop is installed. In the previous chapter, Hadoop was installed at /opt/cluster/hadoop:

   $ ssh [email protected]
   

2. Change to the Hadoop user, or any other user that is running Hadoop, by using the following:

   $ sudo su - hadoop
   

3. Edit the hdfs-site.xml file and modify the parameter to reflect the changes, as shown in the following screenshot:
   
4. dfs.blocksize is the parameter that decides on the value of the HDFS block size. The unit is bytes and the default value is 64 MB in Hadoop 1 and 128 MB in Hadoop 2. The block size can be configured according to the need.
5. Once the changes are made to hdfs-site.xml, copy the file across all nodes in the cluster.
6. Then restart the Namenode and datanode...