Book Image

Hadoop Real-World Solutions Cookbook - Second Edition

By : Tanmay Deshpande
Book Image

Hadoop Real-World Solutions Cookbook - Second Edition

By: Tanmay Deshpande

Overview of this book

Big data is the current requirement. Most organizations produce huge amount of data every day. With the arrival of Hadoop-like tools, it has become easier for everyone to solve big data problems with great efficiency and at minimal cost. Grasping Machine Learning techniques will help you greatly in building predictive models and using this data to make the right decisions for your organization. Hadoop Real World Solutions Cookbook gives readers insights into learning and mastering big data via recipes. The book not only clarifies most big data tools in the market but also provides best practices for using them. The book provides recipes that are based on the latest versions of Apache Hadoop 2.X, YARN, Hive, Pig, Sqoop, Flume, Apache Spark, Mahout and many more such ecosystem tools. This real-world-solution cookbook is packed with handy recipes you can apply to your own everyday issues. Each chapter provides in-depth recipes that can be referenced easily. This book provides detailed practices on the latest technologies such as YARN and Apache Spark. Readers will be able to consider themselves as big data experts on completion of this book. This guide is an invaluable tutorial if you are planning to implement a big data warehouse for your business.
Table of Contents (18 chapters)
Hadoop Real-World Solutions Cookbook Second Edition
Credits
About the Author
Acknowledgements
About the Reviewer
www.PacktPub.com
Preface
Index

Setting the HDFS block size for all the files in a cluster


In this recipe, we are going to take a look at how to set a block size at the cluster level.

Getting ready

To perform this recipe, you should already have a running Hadoop cluster.

How to do it...

The HDFS block size is configurable for all files in the cluster or for a single file as well. To change the block size at the cluster level itself, we need to modify the hdfs-site.xml file.

By default, the HDFS block size is 128MB. In case we want to modify this, we need to update this property, as shown in the following code. This property changes the default block size to 64MB:

<property>
<name>dfs.block.size</name>
    <value>67108864</value>
    <description>HDFS Block size</description>
</property>

If you have a multi-node Hadoop cluster, you should update this file in the nodes, that is, NameNode and DataNode. Make sure you save these changes and restart the HDFS daemons:

/usr/local/hadoop...