Introduction to Hadoop eco system - Overview of HDFS - HDFS Replication Factor

In this article, we will delve into the concept of replication factor, a crucial element of Hadoop Distributed File System (HDFS) that ensures data reliability.

Explanation for the video

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Key Concepts Explanation

Replication Factor Overview

The replication factor in HDFS determines the number of copies of each block of data stored in the cluster. This redundancy enhances data durability and fault tolerance.

hdfs dfs -ls -h /public/retail_db/orders

Default Replication Setting

By default, HDFS maintains a replication factor of 3 copies for each block. This value can be modified in the hdfs-site.xml configuration file.

grep -B 1 -A 3 replication /etc/hadoop/conf/hdfs-site.xml

Impact of Replication Factor

The replication factor impacts storage utilization and fault tolerance. A higher replication factor offers increased reliability but consumes more storage space.

Managing Replication

Admins can adjust the replication factor according to their storage requirements and cluster resilience needs.

Hands-On Tasks

  1. Retrieve the replication status of a file using hdfs dfs -stat %r.
  2. Calculate the storage occupied by a file with a specific replication factor.


To summarize, understanding HDFS replication factor is essential for optimizing storage space and ensuring data resilience in Hadoop clusters. Practicing hands-on tasks will solidify your comprehension of this crucial concept. Get involved with the community to deepen your knowledge and explore advanced HDFS functionalities.

Remember, replication factor plays a key role in maintaining data integrity and fault tolerance in Hadoop environments. Join the discussion and continue your learning journey.

Watch the video tutorial here