Introduction
Distributed file System (DFS) is a set of client and server services that allow an organization using Microsoft Windows servers to organize many distributed SMB / file shares into a distributed file system. DFS provides location transparency (via the namespace component) and redundancy (via the file replication component) to improve data availability in the face of failure or heavy load by allowing shares in multiple different locations to be logically grouped under one folder, or DFS root.
Dfs or Distributed file system was a separately available add-on for the Microsoft Windows NT operating system and a component of the Windows 2000 operating system. The Distributed file system (Dfs) allows file servers and network shares to be logically organized into a single Dfs directory tree.
This simplifies the management of network resources and makes it easier for users to locate and access network resources. From the user’s perspective, the Dfs makes it appear that there is only one server containing a hierarchical tree of resources, while in fact these resources might be distributed across multiple servers in different locations.
The Dfs simplifies directory browsing, offers search tools that simplify locating network resources, and offers administrative tools for building and managing Dfs directory trees. It also eliminates the need for Windows 95, Windows 98, or Windows NT Workstation clients to form multiple persistent network connections, because users require only one persistent connection to the directory tree.

How it works
In the Windows 2000 implementation, you first open the Dfs snap-in for Microsoft Management Console (MMC) to create a Dfs root node. You can then create Dfs child nodes under the root node. Each child represents a shared folder that can be located anywhere on the network. When users want to access a resource on the network, they navigate through the Dfs tree and do not need to know the particular server the resource is located on. Users must have Dfs client software installed on their machines. Dfs client software is included with Windows 2000, Windows NT, and Windows 98. An optional Dfs client can be downloaded for Windows 95 from the Microsoft Web site.

Configuration
Stand-alone: Dfs stores the descr iption of the Dfs file system topology on a single computer. If that computer fails, the entire Dfs system goes down, although users can still access resources the traditional way using mapped network drives or Universal Naming Convention (UNC) paths if they know which servers these resources are stored on and the names of the shares.
Fault tolerant: Dfs stores the Dfs topology information in Active Directory on Windows 2000 domain controllers. This configuration is better for fault tolerance and file replication

When a Server containing Dfs shares fails
If a server containing Dfs shares fails, you can simply move the files to another machine, create new shares, and map the existing Dfs child nodes to the new shares. Your users won’t even know that anything has changed. If you assign a user permission to access a shared folder, that person automatically has permission to access it through the Dfs tree as well.

The challenge for distributed file systems
In a marketplace where the ability to maximize the value of data is critical to business success, organizations need data storage solutions that can improve access to and analysis of data capital. In the past, organizations only expected their distributed file system to be able to scale – it had to be big enough to manage the data today and accommodate data growth tomorrow. High-performance was not necessarily a priority, as most companies assumed that the bulk of file data would be “cold” and wouldn’t need the superfast speeds and minimal latency of “hot” data storage.
Modern workloads have changed that equation though, and today no company wants to be left behind by a distributed file system that can’t keep pace with the requirements of a digital business. Big is no longer enough – today’s storage solutions must be big, fast and efficient. Additionally, a superior distributed file system must offer:

• Lower costs through reduced power consumption and reduced operational expense.


• Improved resource utilization, enabling organizations to get higher ROI from their storage investments.


• Lower total cost of ownership.


• Improved SLAs to meet the strict demands of business needs and compliance requirements.

Benefits of Distributed File System

A distributed file system for storage provides:

• Improved file availability, access time and network efficiency.


• Enhanced scalability and interoperability.


• Data access transparency and location independence.


• A unified view of shared folders and data resources.


• More efficient load-balancing.