HDFS in Hadoop stands for Hadoop Distributed File System. It is used by Hadoop applications as a data storage system. It is designed to store large data sets and stream the same data sets to user applications at a higher bandwidth. It is a file storage and distribution system that works in a Hadoop environment. It has built-in servers named NameNode and DataNode that allows the users to check the cluster status easily.
To learn in-depth about Hadoop and HDFS, you must enroll in Hadoop Training. In this training, you will learn both basic and advanced concepts of Big Data Hadoop. To know more about HDFS, check out this tutorial: