What is Clustered File System?

A clustered file system is a type of file system which is mounted on multiple servers and shared simultaneously by multiple users. There are several approaches to clustering, most of which do not employ a clustered file system (only direct attached storage for each node). Clustered file systems can provide features like location-independent addressing and redundancy which improve reliability or reduce the complexity of the other parts of the cluster. Parallel file systems are a type of clustered file system that spread data across multiple storage nodes, usually for redundancy or performance.

(source: Wikipedia)