Network file systems, such as NFS, use client–server methodology to allow users to access files and directories from remote machines as if they were on local file systems.
System calls on the client are translated into network protocols and retranslated into file-system operations on the server.
Networking and multiple-client access create challenges in the areas of data consistency and performance.
Due to the fundamental role that file systems play in system operation, their performance and reliability are crucial.
Techniques such as log structures and caching help improve performance, while log structures and RAID improve reliability.
The WAFL file system is an example of optimization of performance to match a specific I/O load.