Fjärrfilsystem

Fjärrfilsystem, often abbreviated as NFS, is a distributed file system protocol originally developed by Sun Microsystems. It allows a user on a client computer to access files over a computer network in a manner similar to how local storage is accessed. This makes it possible for multiple users and machines to share data from a central server, improving collaboration and resource utilization.

The core concept of NFS is to export directories from a server to clients. These exported directories appear as local file systems on the client machines. When a client requests to read or write a file within an exported directory, the NFS client software communicates with the NFS server over the network. The server then performs the requested operation on the actual file on its storage and sends the result back to the client.

NFS typically operates using the Remote Procedure Call (RPC) mechanism to facilitate communication between clients and servers. It is designed to be stateless in its core operations, meaning the server does not need to maintain information about the state of each client. This stateless design contributes to its robustness and scalability, as a server crash does not necessarily lead to data loss on the client side and a server restart can resume operations without complex state recovery.

There have been several versions of NFS, with NFSv3 and NFSv4 being the most widely used. NFSv4 introduced significant improvements, including better security features, stateful operations, and enhanced performance. While NFS is widely adopted in Unix-like operating systems, implementations are also available for Windows and other platforms. It remains a fundamental technology for network file sharing in many enterprise and academic environments.