File Systems and Distributed File Systems

• A file system is the method of storing and organizing data on a storage device, such as flash drives, DVDs and hard drives.
• A file is an atomic unit of storage used by the file system to store data.

A file system provides a logical view of the data stored on the storage device and presents it as a tree structure of directories and files.

Operating systems employ file systems to store and retrieve data on behalf of applications.

A distributed file system is a file system that can store large files spread across the nodes of a cluster.

To the client, files appear to be local; however, this is only a logical view.

Physically, the files are distributed throughout the cluster.

This local view is presented via the distributed file system and it enables the files to be accessed from multiple locations.

Examples include the Google File System (GFS) and Hadoop Distributed File System (HDFS).