Implementing an Active Directory Distributed Files System (DFS) on 2008 server.

What is DFS in windows 2008, how to implement DFS system, how to implement DFS system in windows 2008. What is DFS?

Implementing an Active Directory Distributed Files System (DFS) on 2008 server.?

DFS is in use to resolve some issues that are problematic when sharing files over the network with multiple file servers within LAN, WAN & VPN.

Three of the primary problems are:

1. Having multiple file servers over the network confuses the users and makes it tough for them to find their files.

2. Sharing files in a single location creates performance issues when they are accessing  across slow link (WAN or VPN), and a single point of failure when those WAN links go down.

3. It is tough to backup critical files and data when they are detached randomly on multiple file servers at multiple remote locations.

In order to resolve above problem DFS implements has two core technologies, among others:

1. DFS Namespace

2. DFS Replication

1. DFS Namespace:

A DFS Namespace is a virtual directory tree that references or point to one or more actual shares over the network called “targets”.  When a user searches for a file in a DFS namespace are searched. Were it not for the namespace, the user would have to check each server individually for the file.

When someone requests access to a file in a virtual DFS directory tree, a “referral” is returned rather than the actual file.

The referral specifies the file’s location on one of the DFS namespace’s servers.  The DFS client making the Request then retrieves the file from the referred server.

DFS Namespaces can be set up in two modes:

A. Stand-alone

B. Domain-based

                 A. Stand-alone:

1. Accessed via: \\servername\dfsroot\

2. Can be: DC, member-server or stand-alone

3. Namespaces: Supports only ONE

4. Stored in: Registry and system cache

5. Active Directory: Not required

B. Domain-based:


1. Access via” \\domainame\DFSRoot

2. Can be: DC or member-server

3. Namespace: Support MULTIPLE

4. Stored in: Active Directory

5. Active Directory: Required


2. DFS Replication:       

DFS Replication is a multi-master replication service that maintains copies of shared files and folders on multiple servers throughout an organization.

This means that files and folders are duplicated, updated and synchronized by the services on a regular basis, if a file is created, deleted or modified on one server; the same thing automatically occurs at all other servers in the DFS namespace.

The combination of DFS Namespace and DFS Replication provides the following advantages over traditional file sharing:

2.1. This implements fault tolerance for file servers. if a server fails, the files in the virtual DFS namespace are still available on the network via the remaining servers.

2.2 This addresses LAG and bandwidth issues over slower WAN links since servers may be kept at each remote                 location that is part of the DFS namespace.

Clients at those locations may access the files and servers locally at high speed rather than over a slow WAN link. To enhance its bandwidth-saving virtues further, a DFS uses the RDC (Remote Differential Compression) protocol to conserve more bandwidth by only replicating data that has changed in a file since its last replication rather than the entire files.

2.3 This maintains folder and file conformity across an entire organization. Changes made at remote location are replicated and synchronized everywhere.

4. This simplifies backing up and restoring files, folders and data.  The entire virtual directory tree and all its targets can be backed up and restored a single entity.

5. The DFS namespace promotes load balancing akin to clustering and round robin DNS.  That is, if one particular target servers are too busy to service a request, other available target servers in the virtual directory tree can respond instead.

A. Setting up DFS Namespaces

1. Open Server Manager.

2. Select “Add Roles”.

3. Select “File Services”.

4. Select “Distributed File System”.

5. Select “DFS Namespaces” and “DFS Replication” if necessary.

6. Enter the name of the DFS share.

7. Select the namespace type.

8. Select “install” and close.

B. Add Folders to the DFS

1. Open “DFS Management” from Administrative Tools.

2. Right click a namespace and select “New Folder”

3. Enter the folder name and click “Add”

4. When the “Add Folder Target” dialog pops up, select a server and click “NewShared Folder”.

5. When finished, click “OK”.

C. Configure the Referral Order

If you have more than one target server in a DFS namespace share, configure the referral order.  The share will refer clients to a LOCAL server first.  If one is not available, it will then refer servers in the order you specify        If the closest target is unavailable, the next closest one will be used. If the option “client failback” is enabled, when a closer target server that was previously unavailable becomes available again it will be the once referred.

Setting up DFS Replication

 You enable DFS replication among multiple target servers by placing EACH target server in a “Replication Group”.

By default replication groups use “full mesh topology” where every server replicates with each of its partners. Larger networks may opt for “hub/spoke topology”.

By default DFS replication is bi-directional, but this default can be modified.

Each DFS replication group designated a server known as the “Primary Member” . Files on the primary member will overwrite all others.

What is DFS in windows 2008, how to implement DFS system, how to implement DFS system in windows 2008. What is DFS ?