Search icon CANCEL
Subscription
0
Cart icon
Your Cart (0 item)
Close icon
You have no products in your basket yet
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Free Learning
Arrow right icon
Arrow up icon
GO TO TOP
Hadoop Beginner's Guide

You're reading from   Hadoop Beginner's Guide Get your mountain of data under control with Hadoop. This guide requires no prior knowledge of the software or cloud services ‚Äì just a willingness to learn the basics from this practical step-by-step tutorial.

Arrow left icon
Product type Paperback
Published in Feb 2013
Publisher Packt
ISBN-13 9781849517300
Length 398 pages
Edition 1st Edition
Tools
Arrow right icon
Toc

Table of Contents (19) Chapters Close

Hadoop Beginner's Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
1. What It's All About FREE CHAPTER 2. Getting Hadoop Up and Running 3. Understanding MapReduce 4. Developing MapReduce Programs 5. Advanced MapReduce Techniques 6. When Things Break 7. Keeping Things Running 8. A Relational View on Data with Hive 9. Working with Relational Databases 10. Data Collection with Flume 11. Where to Go Next Pop Quiz Answers Index

Time for action – examining the default rack configuration


Let's take a look at how the default rack configuration is set up in our cluster.

  1. Execute the following command:

    $ Hadoop fsck -rack
    
  2. The result should include output similar to the following:

    Default replication factor:    3
    Average block replication:     3.3045976
    Corrupt blocks:                0
    Missing replicas:              18 (0.5217391 %)
    Number of data-nodes:          4
    Number of racks:               1
    The filesystem under path '/' is HEALTHY
    

What just happened?

Both the tool used and its output are of interest here. The tool is hadoop fsck, which can be used to examine and fix filesystem problems. As can be seen, this includes some information not dissimilar to our old friend hadoop dfsadmin, though that tool is focused more on the state of each node in detail while hadoop fsck reports on the internals of the filesystem as a whole.

One of the things it reports is the total number of racks in the cluster, which, as seen in...

lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at $19.99/month. Cancel anytime
Banner background image