Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Network file management (NFM) is a data storage management-related category that was identified and defined in 2004 by several prominent data storage analysts. The term is used interchangeably with NAS virtualization and file virtualization among data storage industry press, analysts and system administrators. The basic idea of NFM is that the rapid, ongoing growth of file data capacity on enterprise networks has led to massive management complexity and accelerating operating costs. NFM is the concept of creating a virtualization layer between the clients and the file servers (or NAS devices). By creating this abstraction layer, System Administrators may simplify the management of the tens, hundreds or even thousands of devices and terabytes of storage resources on their networks. NFM enables the non-disruptive movement of data between servers, preserving the client access path (pathname), policies for automating the placement of data according to its changing needs, and the ability to discover, analyze and report on server and file usage.