The FSRM service queries the DFS server every minute in Windows Server 2008 R2

Consider the following scenario:

• You install the Distributed File System (DFS) role on a computer that is running Windows Server 2008 R2.
• You enable a namespace server on this computer.
• You have another computer that is running a File Server Resource Manager (FSRM). This FSRM has a standard quota.

In this scenario, the FSRM service queries the DFS Namespaces service every minute. Additionally, this scenario may overload the network and the DFS server.

To work around this issue, follow these steps:

1. Start Registry Editor. To do this, click Start
   , type regedit in the Start Search box, and then press ENTER.
   
   
   If you are prompted for an administrator password or for confirmation, type the password or provide confirmation.
2. Locate and then click to select the following registry key:
   HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\SrmSvc\Settings
3. After you select the key that is specified in step 2, point to New on the Edit menu, and then click DWORD Value.
4. Type SharePathRefreshMinutes, and then press ENTER.
5. Right-click SharePathRefreshMinutes, and then click Modify.
6. In the Value data box, type 60, and then click OK.
   
   Note A value to 60 causes the DFS server to be queried one time each hour.
7. On the File menu, click Exit to exit Registry Editor.
8. Restart the SrmSvc service.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

The FSRM service populates the SMB and DFS path caches by using a background thread. These path caches provide paths to users and to administrators. This thread periodically sends queries to the DFS server. However, the background thread stops if the LAN Manager authentication is not started before the SrmSvc service is started. This behavior is a regression from Windows Server 2008. If the services are started in the correct order, the background thread sends queries to the DFS server periodically.

To prevent multiple FSRM servers from querying the DFS server at the same time, the query period is randomized from 80 percent through 120 percent of the target value. By default, the target value is 60 minutes. Therefore, the desired behavior is that the FSRM service sends the DFS requests every 48-72 minutes. However, a registry key is provided to change the update period for testing. The value range is limited to positive integers greater than 0. The registry look up code sets the value to 0 if the registry key is not present.

By default, this registry key is not present on the server. Therefore, the g_refreshPeriodMinutes property is 0. Because it is less than the minimum value of 1, it is set to 1. This regression from Windows Server 2008 causes the SrmSvc service to query the DFS server every minute.