NFS

Network File System (NFS) is a distributed file system protocol that allows a computer to access files over a network as if they were on its local storage. It was developed by Sun Microsystems in the 1980s to enable transparent file sharing among Unix systems. NFS operates over the Remote Procedure Call (RPC) framework, with the common implementation using TCP on port 2049; older setups may rely on auxiliary services such as rpcbind and mountd for initial mounting.

Architecture and operation: A client issues file operations to an NFS server, which exposes files and directories through a set of RPCs. In early versions, NFS servers were stateless, improving reliability and recovery by not keeping per-client state. Clients cache file attributes and data to reduce network traffic, validating with the server as needed. File locking was handled by a separate lock manager, while later NFSv4 integrates stateful semantics, built-in locking, and ACL support. NFS traditionally provides POSIX-like semantics, and most implementations support Linux, BSD, macOS, and Windows with appropriate components.

Version history and features: NFSv2 introduced the basic remote file system over networks. NFSv3 added 64-bit file sizes and improved performance and server scalability, while remaining stateless. NFSv4 unified the protocol around a stateful design, added strong security options (including Kerberos authentication via GSS-API), and simplified namespace access and ACLs. NFSv4.1 introduced parallel NFS (pNFS) to span multiple storage devices and accelerate workloads; NFSv4.2 added features such as file cloning, sparse files, and space reservation.

Deployment and considerations: NFS is widely used for shared storage in Unix-like environments and is supported by Linux, BSD, macOS, and Windows (via optional services). Security concerns arise when NFS is exposed to untrusted networks; recommended protections include firewalls, encrypted transport when available, and strong authentication. Performance relies on network latency and server tuning; caching and mounting options influence throughput. NFS competes with alternatives like SMB/CIFS for mixed-OS environments.