The first network file system—called File Access Listener—was developed in 1976 by Digital Equipment Corporation (DEC). An implementation of the Data Access Protocol (DAP), it was part of the DECnet suite of protocols. Like TCP/IP, DEC published protocol specifications for its networking protocols, which included the DAP.
NFS was the first modern network file system (built over the IP protocol). It began as an experimental file system developed in-house at Sun Microsystems in the early 1980s. Given the popularity of the approach, the NFS protocol was documented as a Request for Comments (RFC) specification and evolved into what is known as NFSv2. As a standard, NFS grew quickly because of its ability to interoperate with other clients and servers.
The standard continued to evolve into NFSv3, defined by RFC 1813. This iteration of the protocol was much more scalable than previous versions, supporting large files (larger than 2GB), asynchronous writes, and TCP as the transport protocol, paving the way for file systems over wide area networks. In 2000, RFC 3010 (revised by RFC 3530) brought NFS into the enterprise setting. Sun introduced NFSv4 with strong security along with a stateful protocol (prior versions of NFS were stateless). Today, NFS exists as version 4.1 (as defined by RFC 5661), which adds protocol support for parallel access across distributed servers (called the pNFS extension).
The timeline of NFS, including the specific RFCs that document its behavior, is shown in Figure 1.
Figure 1. Timeline of NFS protocols Amazingly, NFS has been under development for almost 30 years. It represents an extremely stable (and portable) networked file system that's scalable, high performing, and enterprise quality. As network speeds increase and latencies decrease, NFS continues to be an attractive option for serving a file system over a network. Even in local network settings, virtualization drives storage into the network to support more mobile virtual machines. NFS even supports the latest computing models to optimize virtualized infrastructures.

The secure shell, ssh, and its companion, scp, are tools that I use more or less on a daily basis. Being able to move files between machines without having to setup SAMBA or NFS is very handy when working with multiple systems. All that you need is to enable the secure shell daemon - sshd.
Before we go into the details of the sshfs, let's run through a quick re-cap of ssh. The secure shell daemon runs on port 22 by default. It makes it possible to run an encrypted shell session. With the -Y flag, you can even run X11-forwarding, allowing you to run X11, i.e. graphical, programs on the remote machine and displaying the windows on the terminal that you are sitting at.
You can configure sshd through the /etc/ssh/sshd_config file (that is the location on my Kubuntu machine). Here, you can disable root access, older protocols, X11 forwarding, etc. The notion is that the more limits you put on the remote access, the more secure your system is from potential attacks. You might also want to tune your hosts.allow and hosts.deny files if you plan to expose sshd to the Internet. There are many guides on hardening servers and ssh, so I will not go into details.
To get things up and running, what you need to do is to install sshd. In Ubuntu, that means the openssh-server package. For external access, you also need to enable port forwarding of port 22 in your router/firewall and find your external IP. Now, you should be able to log onto your machine using your normal user credentials.
$ ssh user@192.168.1.100 user@192.168.1.200's password:
Having entered the password, you should now have full access to the remote system.
The handy scp command, secure copy, works in much the same way. To copy the file test.txt to user's remote home directory, simply enter:
$ scp test.txt user@192.168.1.100:
As before, you will be prompted for a password. You can copy the other way around as well. The command below demonstrates how to copy a file with an absolute path, i.e. not in the home directory of user, to your local machine.
$ scp user@192.168.1.100:/var/log/messages remote-messages
These two commands means that you can browse the file system, and freely copy files between machines. What sshfs does is that it exposes this functionality as a file system that you can mount. Before we look into how, let's have a quick look at sshfs.
The sshfs is implemented using FUSE, and relies on the sftp part of ssh to access the remote computer. As a remote file access protocol, sshfs is not very good. For instance, multiple users writing to the same file at once can create havoc. The benefits are the inherit security and that it is easy to setup.
So, how to use it. Let's look at a very short demonstration.
$ sshfs user@192.168.1.100: remote-home
$ ls remote-home
Desktop Documents Downloads Music
$ fusermount -u remote-home
The initial sshfs command mounts the user's home directory to remote-home. You can specify another path after the colon to mount any other part of the remote file system. Access is only restricted by user's access rights.
Using ls, or any other ordinary command, will work as if the remote home directory was mounted locally. All tools work. For instance, you can log onto your remote machine and build software using your locally installed setup of build tools.
To unmount the filesystem, the fusermount command from the FUSE utilities package is used.
To summarize, sshfs an easy setup remote file access tool. It needs to be used with care if multiple users are involved. It makes it dead easy to temporarily access remote file systems, as well as mounting file systems from virtual machines for easier access and monitoring, as well as for remote installation, compilation and debugging. All-in-all, one of the tools I always keep handy in my toolbox

NFS (Network File System) is basically developed for sharing of files and folders between Linux/Unix systems by Sun Microsystems in 1980. It allows you to mount your local file systems over a network and remote hosts to interact with them as they are mounted locally on the same system. With the help of NFS, we can set up file sharing between Unix to Linux system and Linux to Unix system.
Benefits of NFS
1. NFS allows local access to remote files.
2. It uses standard client/server architecture for file sharing between all *nix based machines.
3. With NFS it is not necessary that both machines run on the same OS.
4. With the help of NFS we can configure centralized storage solutions.
5. Users get their data irrespective of physical location.
6. No manual refresh needed for new files.
7. Newer version of NFS also supports acl, pseudo root mounts.
8. Can be secured with Firewalls and Kerberos.
NFS Services
Its a System V-launched service. The NFS server package includes three facilities, included in the portmap and nfs-utils packages.
1. portmap : It maps calls made from other machines to the correct RPC service (not required with NFSv4).
2. nfs: It translates remote file sharing requests into requests on the local file system.
3. rpc.mountd: This service is responsible for mounting and unmounting of file systems.
Important Files for NFS Configuration
1. /etc/exports : Its a main configuration file of NFS, all exported files and directories are defined in this file at the NFS Server end.
2. /etc/fstab : To mount a NFS directory on your system across the reboots, we need to make an entry in /etc/fstab.
3. /etc/sysconfig/nfs : Configuration file of NFS to control on which port rpc and other services are listening.