What Is a Network File System? NFS Meaning Explained

Sharing files across a network is an important part of digital communication. This is exactly what Network File System, or NFS, is designed for. Originally developed for local file sharing, it allows users to access files stored on remote servers. This makes it a useful tool for organizations that require large-scale file sharing between different systems. In this article, learn what NFS is, how it works, and how it transforms our digital interactions.

What is NFS?

Network File System (NFS) is a network protocol that allows a client computer to access files over a network as if they were on its local storage. This means that you can open, read, write, and delete files and directories on a remote server as easily as you would on your own computer.

Simply put, NFS is a distributed file system protocol. It defines the network file system, which is the way files are stored and retrieved from storage devices across computer networks.

Administrators originally designed this system for local file sharing across Unix workstation. Sun Microsystems released it in 1984. The Internet Engineering Task Force (IETF) first published NFS protocol specification as an Internet protocol in RFC 1094 in 1989. Network File System version 2, or NFSv42, which is the latest iteration of the NFS protocol, is documented in RFC 7530.

Files transferred across a network with Network File System (NFS)

Like many other protocols, NFS utilizes the Remote Procedure Call (RPC) system. It specifically uses the Open Network Computing Remove Procedure Call (ONC RPC) system. Network File System also uses TCP/IP for communication.

System administrators use NFS to share the whole or a portion of a file system on a networked server so that a remote computer can access it. It also allows them to consolidate resources onto centralized servers on the network.

For example, an employee who travels throughout the year can continue to access necessary company files from different devices regardless of where they are geographically. The files are accessible as local files for users in different places.

NFS continues to evolve and now exists as an open-source standard, allowing implementation on all operating systems. It supports more than just file sharing; now, it also supports security and scalability.

How does NFS work?

The principle behind NFS is quite simple: it enables different users to collaborate and share data seamlessly. It provides an efficient way to share files between computers running different operating systems.

NFS operates on the client-server model. The server hosts the files to transfer while the client computers access these shared resources. Therefore, the architecture consists of a client-side file system and a server-side file system. Network File System works by allowing a client system to access files on a remote server as if they were located on the local system.

When a client computer issues a request for a file, Network File System uses the RPC protocol to communicate with the server and retrieve the requested data. The server then processes the requests and returns the results to the client. This communication occurs over the network, enabling the client to access files from a remote location.

NFS uses various Remote Procedure Calls to perform operations, such as looking up, reading, writing, creating, or removing files. It also supports other RPCs for more advanced operations, like file locking and attribute caching. It's a commonly used protocol for file servers.

Network File System is widely used to provide file-sharing solutions across heterogeneous computing environments. Its implementation is available for most modern operating systems. It works on:

  • Linux
  • IBM AIX
  • Microsoft Windows
  • OpenBSD
  • Hewlett Packard Enterprise HP-UX
  • Oracle Solaris
  • NetBSD

In addition to these operating systems, cloud vendors use NFS protocol for cloud storage. A good example is Amazon Elastic File System (Amazon EFS) or Microsoft Azure NFS file shares.

Features of NFS

Network File System is a stateless protocol for distributed file sharing. Functioning on the application layer, admins can configure the protocol as a centralized storage solution and secure it with firewalls for additional protection if the user so desires.

NFS is implemented primarily on systems running the TCP/IP protocol suite. Therefore, users can transfer files between computers of different operating systems, like between a Windows and non-Windows operating system.

NFS installation and configuration

Network File System is one of the most transparent ways to handle shared storage within an organization. Here's how to install and configure NFS to make it function.

How to install an NFS server

To install the NFS server, you need to follow these steps.

  1. Open the terminal and run the command sudo apt-get install nfs-kernel-server to install the necessary packages.
  2. Edit the /etc/exports file to specify the directories you want to share.
  3. Restart the NFS server using the command sudo systemctl restart nfs-kernel-server.

Once the NFS server setup is complete, you can start sharing files and directories with other machines on the network. Ensure that the necessary firewall rules are in place to allow NFS traffic.

How to configure an NFS server

Configure NFS exports after installing the NFS server. This involves specifying the directories on the server that are available to clients. The configuration occurs in the /etc/exports file, which contains a list of exports along with their options.

Each export is defined on a new line, and the syntax follows the pattern: directory client(options). The directory is the path being exported, and the client is the IP address of the client machine.

Admins can use options to specify permissions, access control, and other settings. It's important to carefully configure the exports to ensure proper access and security. After configuring exports, the NFS server needs to restart for the changes to take effect.

Mounting NFS shares

Moving forward, mount NFS shares on your local systems to access them. You can use the mount command followed by the remote server's IP address, the exported directory path, and the local mount point. Consider the following example:

$ mount server:/shared /mnt/nfs

This allows you to treat the remote NFS shares as if they were a part of your local file system. After mounting the NFS share, you can navigate to the mount point and access the files as you would with any local files.

Note that if the NFS server becomes available, it will affect any processes accessing the NFS mount shares. Therefore, it's crucial to ensure the reliability of the NFS server for uninterrupted access to the shared files.

Versions of NFS

Sun Network Filesystem

Sun Microsystems released the first implementation of the Network File System in March 1984. It marked the inception of remote file sharing. The goal of the protocol was to provide transparent, remote access to file systems.

NFS was a revolutionary technology at the time and it quickly became the standard for NFS in Unix environments. However, this oldest version of NFS was stateless, meaning that it didn't maintain information about the open files. This made it simple, but less secure.

NFSv2

NFS version 2 (NFSv2), as defined in RFC 1094, emerged in March 1989. The designers involved in its creation aimed to keep the server side stateless, implementing locking outside of the core protocol. It originally operated entirely over UDP through an IP network, but does not support many necessary features for modern enterprise deployments, like security, scalability, and high availability.

It backed symbolic links, a type of tile that points to another file, and has a maximum file size of 2 GB due to 32-bit limitations. However, it's outdated and no longer used today.

NFSv3

Developed in June 1995, NFSv3 is specified in RFC 1813. Version 3 introduced a number of improvements over its predecessor, such as:

  • More detailed error information
  • The ability to use TCP as a transport protocol
  • More file attributes for better compatibility with various file systems
  • Support for asynchronous writes on the server
  • An extended file offset of 64 bits, enabling the NFS client to handle file sizes more than 2GB

NFSv3 is still in use and supported by major operating systems.

NFSv4

Version 4 was first mentioned in RFC 3010 in December 2000 and revised in April 2003. Most users increasingly look towards NFSv4 because it's the latest version with an updated protocol.

Version 4 introduced state as opposed to the stateless Version 2 and Version 3. The version also introduced new features, including support for IPv6, file delegation, and the integration of Kerberos for authentication and security.

NSFv4 is more scalable than previous versions, operating over a single network port for easier management in firewall-restricted environments. It also implements Access Control Lists for greater granular control over file permissions.

NFSv4.1

NFS version 4.1 introduced some significant improvements over its predecessor. It was released in January 2010. It brought standardized parallel NFS, which allows greater I/O parallels, and session-based operations to improve the management of network resources.

In version 4.1, users have access to support for UTF-8 encoding, internationalization, and a new session model. They also have enhanced security thanks to new stronger authentication mechanisms.

NFSv4.1 has backwards compatibility with NFS4, which allows users to upgrade without worrying about breaking existing installations.

NFSv4.2

To build on the features of version 4.1, version 4.2 introduced several key enhancements in 2016. It added support for data deduplication and extended security options by including support for the Remote Direct Memory Access (RDMA) Transport. This newer version also offers enhanced server side copy and application data blocks, allowing applications to manage data placement on the storage media. Ultimately, version 4.2 can handle files more efficiently, particularly sparse files.

Benefits of Network File System

Network File System offers a number of benefits to organizations. It provides easy access to files and directories across different operating systems, allowing for seamless file sharing. It also reduces storage costs by enabling the sharing of storage resources among multiple clients.

With these things comes improved performance; the fact that it caches frequently accessed data reduces network traffic and latency. It simplifies administration with its central management and offers an easy setup.

NFS is an open protocol, which means the specifications are publicly available. Anyone who wants to use this system can implement the protocol.

Limitations of Network File System

Network File System isn't a flawless protocol. It depends on RPCs to perform all of its operations, such as reading files. This, then, raises security concerns; RPCs can be vulnerable to internal threats, especially man-in-the-middle attacks.

Additionally, Network File System can be difficult to scale to large numbers of clients and servers, as all NFS traffic must flow through the NFS server.

Frequently asked questions

What is the difference between NTFS and NFS?

NTFS (New Technology File System) is a Windows-based proprietary file system for local storage. Network File System, on the other hand, is a protocol for sharing files over a network.

What protocol is used in NFS?

All versions of NFS can use Transmission Control Protocol (TCP) running over an IP network.

Can NFS be used with Windows systems?

Yes, although it's predominantly used with Unix or Linux. It can, however, also be used with Windows systems.

Is Network File System secure?

It has security concerns, particularly in its earlier versions. However, more recent versions like NFSv4 have integrated security features like Kerberos authentication.