When Microsoft originally introduced the Distributed File System (DFS), it did so with the intention of making things easier on the end user. The idea was that users did not need to know which server resources actually existed on it. They could simply access the file system through a special share and access all of the data they needed, regardless of whether it existed in a central location or was spread across a number of different servers.
Although making things easy on users is always good, I think that DFS is a lot more useful for load balancing and fault tolerance. DFS can be used to distribute the user workload across multiple replica file servers. Furthermore, if a replica server were to fail or if an administrator needs to take a server offline for maintenance, users could continue to access replica servers without interruption. (In part two, I will discuss load balancing and fault tolerance in more detail.)
Today, in part one, I'm going to show you how to set up a distributed file system on a Windows 2003 server.
Step 1: Set up the console
Begin the process by entering the Microsoft Management Console (MMC) command at the Run prompt. When you do, Windows will load an empty Microsoft Management Console. Now, select the Add / Remove Snap-In command from the console's File menu. Windows will now display the Add / Remove Snap-In properties sheet. At this point, click the Add button that's found on the properties sheet's Standalone tab to reveal a list of the available snap-ins. Select the Distributed File System option from the list and click the Add button, followed by the Close and OK buttons.
Step 2: Create a DFS root
A root is basically the top level of the DFS hierarchy. A root can include multiple shared folders. To create a root on the server that presently contains some of your data, right click on the Distributed File System container within the console and select the New Root command from the shortcut menu. This will cause Windows to launch the New Root wizard. Click Next to bypass the wizard's Welcome screen. The wizard will now ask if you want to create a standalone root or a domain root. Domain roots only exist in Windows Server 2003. They support automatic data replication. For the purposes of this article, select the domain root option and click Next.
The next screen asks you which domain will be used to host the root that you are creating. Select the appropriate domain and click Next. You must now enter the name of the server that will host the newly created root. The server must be a member of the domain that you selected in the previous step. Enter the server's fully qualified domain name and click Next.
Step 3: Name the root The next screen requires you to enter a name for the root that you are creating. Windows will create a share name that is the same as the root name that you enter, so be sure not to duplicate an existing share name. I also recommend that you enter a description to help you remember what the root does. Click Next to continue.
Step 4: Folder selection
This screen asks you for a folder that Windows can assign the share to. I recommend selecting the folder that already contains your data. Click Next followed by Finish to create the root.
Your DFS share should now be active. To confirm that the root is functional, right click on it and select the Check Status command from the shortcut menu. The status should display as online.
How to set up a replica server
In preparation for part two of this series, I want to show you how to set up a replica server.
Begin the process by going to the server you want to set up as a replica and selecting a volume with plenty of free disk space. After doing so, create a folder on that volume that can be used to store the data you will be replicating to the server.
After creating the folder, share the folder using the same share name as you assigned to the DFS root. I recommend giving everyone full control at the share level and using NTFS permissions to secure the data instead of relying on share-level permissions. After creating the share, you may have to wait for about 15 minutes for the network to become aware of the share. While you are waiting, open the Services console and start the Distributed File System service.
Now, return to the DFS console, right click on the DFS root that you created earlier and select the New Root Target command from the shortcut menu. You will now be prompted to enter the name of the server on which you want to create the root target. On my system, I had to enter the server's NetBIOS name rather than it's fully qualified domain name in order to make Windows recognize the server. Make your selection and click Next. After a bit of a delay, you will see a screen informing you that you have completed the wizard. Click Finish to continue.
At this point, your DFS root should be up and running. Now, you will have to initiate the replication process. To do so, right click on the DFS root and select the Configure Replication command from the resulting shortcut menu. Windows will launch the Configure Replication wizard. Click Next to bypass the wizard's Welcome screen and you will be prompted to select the initial master. Select the share that presently contains data and click Next. The next screen that you see asks you to select a replication topology. I recommend using a full mesh topology. Click Finish. When you do, you may see a message indicating that the File Replication Service needs to be configured to be automatically started on the replica server. If that's the case, then use that server's Services console to change the File Replication Service's startup type to automatic. Start the service and then click Yes to retry the replication configuration.
Click here to read "DFS benefits go beyond the user, part 2."
Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. Brien has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer he has written for Microsoft, CNET, ZDNet, TechTarget, MSD2D, Relevant Technologies and other technology companies. You can visit Brien's personal Web site at www.brienposey.com.
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