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Setting Up the Distributed File System - DFS

October 2008

Table of Contents  

Distributed File System (DFS) is one of the most useful and underutilized features of Active Directory (AD) and Windows file servers. With DFS, system administrators can make it easy for users to access and manage files that are physically distributed across a network. With DFS, you can make files distributed across multiple servers appear to users as if they reside in one place on the network. Users no longer need to know and specify the actual physical location of files in order to access them.

Here is a simple example of what you can do:

The Butterfly Science Department has three file shares on three different servers:

\\svc01\Users
\\svc02\Groups
\\svc03\Projects

The admin has mapped three drive letters for users to access the files on the different servers.

With DFS, all these can be combined under a single virtual file system using DFS and be mapped to a single drive. Additional file shares can be added or existing ones changed on the fly without users having to know about it.

Prerequisites

Basic Setup Procedure

Note: The text of the following documentation lists the root domain of the U-M Windows Forest correctly as adsroot.itcs.umich.edu. The screenshots, however, were taken from the test forest and thus show the adsroot.itd.umich.edu.

  1. contact the ITS Service Center to set up the initial DFS folder for your unit. Once the initial Namespace setup is complete, it will be delegated to your OU Admin group.

  2. ITS will create DFS Roots on one or two servers:

    1. In our Butterfly Science Department example, we will use SVC01 and SVC02. These can be the same or different servers as the file shares.

    2. A directory named C:\DFSRoots\ButterflyScience will be created on each server by ITS. (Do not make any changes to this directory or store files in it.)

  3. (This step can be done by the OU Admin, but ITS can create the initial folder links for you)
    Open the DFS Management Snap-in and the new Namespace:

    1. Start the DFS Management Snap-in.

    2. Select Action > Add Namespaces to Display from the menu.

    3. Set scope to "adsroot.itcs.umich.edu" and click the Show Namespaces button.

    4. Select \adsroot.itcs.umich.edu\ButterflyScience

  4. Add folder targets:

    1. Select Action > New Folder.

    2. In the Name field, enter "Users".

    3. Click the Add button to select the file share.

    4. Enter the file share name or browse. You can also create file shares on the fly.

    5. Repeat for additional file shares.

  5. Your users can now map a drive to the following file share and see all the folder targets on the different servers:

    \\adsroot.itcs.umich.edu\ButterflyScience

Advanced Features

Campus DFS Hierarchy

Your DFS hierarchy is a member of the campus DFS hierarchy in addition to your own DFS hierarchy. The campus DFS is accessed here:

\\adsroot.itcs.umich.edu\Dfs

For example, the Butterfly Science DFS is available at both:

\\adsroot.itcs.umich.edu\ButterflyScience
\\adsroot.itcs.umich.edu\Dfs\ButterflyScience

Using WebDAV and SFTP

You can use your DFS Root as a target for remote access using WebDAV or SFTP. In this way, all your file storage is accessible from one place.

Nested Folders

Perhaps you want a more complex file structure. For example, what if you wanted a Department Folder and each folder beneath that were a share on a separate server?

  1. Open the DFS Management Snap-in and add your Namespace.

  2. Add folders:

    1. Select Action > New Folder.

    2. In the Name field, enter "Department".

    3. Click the OK button to finish. Do not add a file share.

  3. Notice that Department does not have a shortcut icon because it is a DFS namespace folder.

  4. Add folder targets under Department:

    1. Right-click on "Department".

    2. Select Action > New Folder.

    3. In the Name field, enter "Marketing".

    4. Click the Add button to select the file share.

    5. Enter file share name or browse. You can also create file shares on the fly.

    6. Repeat for additional file shares such as "Sales".

  5. DFS now looks like this:

  6. Users see this. Four folders at the root with a total of five folders with data on five different servers!

DFS Replication

It is possible to specify multiple file shares for the same folder target and replicate data between them. This is only meant to be used for Read-Only file shares because users access a randomly selected file share. If two users write to the same file on different file shares, the last writer wins.

Resources

Microsoft's Distributed File System overview