Windows Server 2008: The Definitive Guide

The Distributed File System

The Distributed File System (DFS) is a technology that allows several distinct filesystems, potentially on multiple servers, to be mounted from one place and appear in one logical representation. The different shared folders, which likely reside on different drives in different server machines, can all be accessed from one folder, known as the namespace. Folder targets serve to point from shared folder to shared folder to mimic a directory tree structure, which can be rearranged and altered according to a particular implementation's needs. DFS also allows the clients to know only the name of the share point and not the name of the server on which it resides, a big boon when you field help-desk calls asking, "What server is my last budget proposal located on?"

DFS namespaces come in two basic flavors: standalone namespaces, which store the folder topology information locally, and domain-based namespaces, which store the topology structure in Active Directory and thereby replicate that information to other domain controllers. In this case, if you have multiple namespaces, you might have multiple connections to the same data—it just so happens that they appear in different shared folders. You even can set up two different share points to the same data on two different physical servers, because DFS is intelligent enough to select the folder set that is geographically closest to the requesting client, saving network traffic and packet travel time.

DFS in Windows ...