NFS (Network File System) overview
NFS (Network File System) is a file-sharing protocol used by ESXi hosts to communicate with a NAS (Network Attached Storage) device over a standard TCP/IP network. A NAS device is a specialized storage device connected to a network, providing data access services to ESXi hosts through protocols such as NFS.
NFS datastores are used in much the same way as VMFS datastores. They can hold virtual machine files, templates, ISO images, and other date. An NFS volume supports advanced vSphere features such as vMotion, DRS, and HA. ESXi includes a built-in NFS client that uses NFS v3 to communicate with the NFS server.
To use NFS as a shared repository, you must create a directory on the NFS server and then mount that directory as a datastore on all hosts. Note that ESXi hosts must have the read/write permissions on the NFS server and the read/write access must be allowed for the root system account. We will learn how to do that in some later section.
In the picture above you can see that the datastore My NFS Datastore is using NFS 3 as its file system.