Windows Server 2008 R2 file and print services : Administering Distributed File System Services (part 1) - Configuring and administering DFS Namespaces

DFS was first introduced in Windows 2000 as a way to provide centralized access to network share folders located on different file servers throughout the network. Instead of accessing a server and share, users simply access the DFS access point which connects them to the correct shared folder. Additionally, DFS can provide shared folder redundancy by having several replicated copies of a single shared folder. DFS Replication (DFSR) was first introduced as a feature in Windows Server 2003 R2 and DFSR provides the ability to replicate a single shared folder between different file servers to provide redundancy and centralized management of shared folders. Both DFS technologies exist in Windows Server 2008 R2 as role services for the file server role. Using a combination of DFS Namespaces and DFSR, you can provide a more manageable, centralized, and highly available file-sharing infrastructure. Figure 1 depicts what a typical DFS share might look like. In this section, we will explore the aspects of creating, configuring, and administering DFS Namespaces and DFSR.

Figure 1. Example DFS Namespace deployment.

Configuring and administering DFS Namespaces

DFS Namespaces are used to publish shared folders under a single directory structure. Before setting up a new DFS Namespace, we need to add the DFS Namespace role service. If the server that you plan to set up DFS on already has shared folders, you will not need to add the file services role but only the DFS Namespace role service. Windows Server 2008 R2 supports two namespace types:

• Domain-based namespace —A domain-based namespace stores the DFS configuration in Active Directory providing redundancy and high availability to the DFS tree. This effectively removes the DFS root server as a single point of failure. If the domain functional level is at least Windows Server 2008 and the forest functional level is at least Windows Server 2003, then Windows 2008 DFS mode can be used for domain-based Namespaces providing additional features such as ABE and increased scalability.

• Stand-alone namespace —A stand-alone namespace stores DFS configuration on the local computer. High availability and redundancy can be achieved by using Windows cluster features.

To add the DFS Namespace role service, perform the following:

1.	Open Server Manager and select the node Roles | File Services.
2.	In the middle pane click the link Add Role Services.
3.	Select the DFS Namespaces option as seen in Figure 2. Then click Next. Figure 2. Adding DFS Namespace Role Service.
4.	You can now choose to create a new DFS Namespace or create the namespace later. For this exercise, select the option Create namespace later using the DFS Management snap-in in Server Manager. Then click Next.
5.	Click Install to install the DFS Namespace role service.

Once the DFS Namespace role service has been installed, DFS Namespaces can be created and managed from Server Manager by selecting the node Roles | File Services | DFS Management | DFS Namespaces. To create a new DFS Namespace, perform the following:

1.	Right click on the DFS Namespaces node and select the option New Namespace (see Figure 3). This will launch the New Namespace Wizard. Figure 3. Creating New DFS Namespace.
2.	Select the server that will host the DFS Namespace (see Figure 4). This can be a Windows cluster to provide high availability. Then click Next to continue. Figure 4. DFS Namespace host.
3.	Enter a name for the Namespace (see Figure 5). This is the name by which the namespace will be referred to by clients. Additionally, you can set permissions on the DFS root by clicking the Edit Settings button. In most cases, the default option of All users have read-only permissions will be sufficient as this access is for DFS only and not the target shared folder within the tree. Click Next to continue. Figure 5. DFS Namespace Name.
4.	We now need to select the DFS Namespace type. In our example, we will use a domain-based namespace. Select the option Domain-based namespace, and select the option Enabled Windows Server 2008 mode (see Figure 6). Then click Next. Figure 6. Selecting DFS Namespace Type.
5.	Verify the configuration settings and then click Create. You should receive a confirmation that the namespace was created successfully.

The namespace will now appear in Server Manager under the Namespaces node as seen in Figure 7. Notice that DFS Namespaces are accessed using the Active Directory domains FQDN and namespace name (\\contoso.com\Data).

Figure 7. Newly Created DFS Namespace.

You can now create folder targets underneath the namespace. These folder targets will link to shared folders on file servers across your corporate network. To create a new target folder underneath the namespace, perform the following:

You have now added a target folder that links users to the shared folder ClientData on the server labfs1. This shared folder can be accessed by simply browsing the DFS root and selecting the ClientData folder. This folder will refer the client to the ClientData folder on the appropriate file server. In this case, the server would be labfs1. You can create links to other shared folders on various servers on your network. They can then be accessed via the DFS root\\domain FQDN\DFS Root Name.