The Hadoop Distributed File System (HDFS) is a distributed file system designed to run on commodity hardware.
User Guide：http://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/HdfsUserGuide.html
Web Interface
With the default configuration, the NameNode front page is at http://namenode-name:50070/
Shell Commands
See http://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/FileSystemShell.html