HOW TO: Use DFS on a Server Cluster to Maintain a Single Namespace (301588)

SUMMARY

This article describes how to configure Distributed File System (DFS) on a Windows server cluster to maintain a single namespace for file shares. This configuration makes it easier for users and administrators to remember where files are located, maintain highly available file servers, and host file shares across multiple nodes for scalability.

The scenario in this section describes how to create a clustered file server for four different groups while maintaining a single connection point.

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Scenario

This scenario describes how to maintain a single namespace for users home directories yet distribute the load between four cluster nodes for the EAST, WEST, NORTH, SOUTH sites. To do so, you can create a four-node Windows cluster that is comprised of six cluster groups:

• Cluster Group
• DFS Root Group
• EAST FileShare Group
• WEST FileShare Group
• NORTH FileShare Group
• SOUTH FileShare Group

The network name resource that is in the DFS root group is the resource that is used by all users (or login scripts) to connect. When users connect to this virtual server, they are presented with EAST, WEST, NORTH, and SOUTH folders. The different folders are hosted on one of the four nodes. This scenario requires a total of six disks on the shared bus. This configuration allows the optimal situation; it includes a disk in the cluster group and in the DFS root group, plus one for each of the site groups.

The following procedure describes how to create this distributed file server. This procedure assumes that the Cluster service is installed on all nodes, and that there are five default groups (the cluster group, Group 0, Group 1, Group 2, Group 3). Each group has a disk starting with the cluster group, with "Disk Q" going up to "Disk V" in Group 3.

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Create Four Independent Virtual Servers

1. Create a folder on Disk S named "EASTUSERS", and then create folders for each of the users in the EAST region under EASTUSERS.
2. Start Cluster Administrator, and then click Configure Application on the File menu.
3. In the Cluster Application Wizard, click Next, click Create a new virtual server, and then click Next.
4. Click Use an existing resource group, click the first group (Group 0) in the list of groups that is displayed, and then click Next.
5. In the Name box, type EAST FileShare Group, and then click Next.
6. In the Network name and IP address boxes, enter a virtual server name and an IP address, such as "EASTFILESERVER", and then click Next.
   
   NOTE: End users cannot connect to this virtual server directly; this virtual server is only present for administrative purposes.
7. In the Advanced Properties for the New Virtual Server page, click Next.
8. Click Yes, create a cluster resource for my application now on the Create Application Cluster Resource page, and then click Next.
9. In the Resource Type box, click File Share, and then click Next.
10. In the Name box, type EAST FileShare, and then click Advanced Properties.
11. Click the Dependencies tab, and then click Modify.
12. Add the physical disk (Disk S) and the network name (EAST FileShare Group Name) as dependencies, and then click OK twice.
13. Click Next.
14. In the Share name box, type EASTUSERS$ (when you add the dollar sign [$], the share is hidden from casual browsing).
15. In the Path box, type S:\EASTUSERS.
16. Click Next, and then click Finish.
17. Right-click the EAST FileShare Group, and then click Bring Online.
18. Repeat steps 1 to 17 for the WEST, NORTH, and SOUTH regions using Group 1 with Disk T, Group 2 with Disk U, and Group 3 with Disk V.

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Create a DFS Root

You now have four independent virtual servers that can be failed back and forth between the four nodes. Next, you must create the DFS root that is used for users to connect to or login scripts to map drives to:

1. Create a folder on Disk R named "USERSHARE".
2. In Cluster Administrator, click Configure Application on the File menu, and then click Next.
3. Click Create a new virtual server, and then click Next.
4. Leave the selection in the Create a new resource group box, and then click Next.
5. In the Name box, type DFS Root Group, and then click Next.
6. Type a network name and IP address for this virtual server, such as NORTHAMERICA, and then click Next.
   
   NOTE: This virtual server is the virtual server that all users connect to regardless of their location.
7. Click Next, verify that Yes, create a cluster resource for my application now is selected, and then click Next.
8. In the Resource Type box, click File Share, and then click Next.
9. In the Name box, type DFS Root FileShare, and then click Advanced Properties.
10. Click the Dependencies tab, and then click Modify.
11. Add DFS Root Group Name and Disk R as dependencies, and then click OK twice.
12. Click Next.
13. In the Share name box, type USERSHARE.
14. In the Path box, type R:\USERSHARE.
    
    NOTE: You can use the local disk in each node because there is no data being copied locally. DFS requires a share to be set up but does not copy any real data to it. A sixth shared disk could be used and would be preferable.
15. Click Advanced, and then click DFS root.
16. Click OK, click Next, and then click Finish.
17. Right-click DFS Root Group, and then click Bring Online.
18. Start the Distributed File System program. \\NORTHAMERICA\usershare is listed under the root.
19. Right-click \\NORTHAMERICA\usershare, and then click New Link.
20. Type EASTUSERS in the Link name box, in the Path to target (shared folder), type the path to the EASTUSERS virtual server and share name ( \\EASTFILESERVER\EASTUSERS$), and then click OK.
21. Create links to the WEST, NORTH, and SOUTH regions by following the preceding two steps and pointing to the respected virtual servers and share names.
22. Test the DFS share by connecting to \\NORTHAMERICA\USERSHARE. There are EAST, WEST, NORTH, and SOUTH shares to be connected as well.

Clients running Windows 2000 and later versions of Windows can map drives beyond the first share level. In the preceding example, the logon scripts could effectively map a drive letter to the following location: You can place the EAST, WEST, NORTH, SOUTH file share groups on the different cluster nodes for manual load balancing.

As with the Windows 2000 cluster, DFS domain roots are not supported as cluster resources. DFS domain roots are published in Active Directory, which implies some fault tolerance. See "Help and Support" for information about creating DFS domain roots.

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