DFS and mapped drives RRS feed

  • General discussion

  • I've recently had an issue with intermittent drive mappings not working to DFS shares, after chasing down what it wasn't, I was able to pin it down to what it was.
    I'm posting this in case anyone else has these issues as well.
    I had complaints from some clients at one site that some of their drive mappings were not showing up. Server 2008 R2 domain. Looking into the problem, I saw that the problem was with both XP SP3 and 7 SP1 clients. I noticed that the server\share drives mapped without fail every time, but the DFS shares were hit and miss, but a client either got all DFS mappings or none. All methods were affected GP Pref, logon script, ADUC home drive mapping.


    After completing a 2003R2 to 2008R2 domain change, I noticed the last server DC1 migrated was missing the root structures in the registry key: HKEY_LOCAL_MACHINE\Software\Microsoft\Dfs\Roots\DomainV2

    The other servers migrated first and second DC2 and DC3 had the root structures under the aforementioned key. I also noticed that my DFS structure was still in 2000 mode. Instead of creating the reg keys, I decided to follow "Migrate a Domain-based Namespace to Windows Server 2008 Mode" from http://technet.microsoft.com/en-us/library/cc753875.aspx knowing that I would be recreating all my DFS root structures in the V2 format anyway.

    Recreating the DFS roots proved to be problematic, as removing them from the DFS GUI seem to work until I tried to recreate them. I received a "\\<var>domain</var>\<var>root</var>\<var>folder</var>: Properties cannot be set on the folder. The request is not supported" error. Trying to remove them through the cmd prompt resulted in an error that they didn't exist.

    Looking in ADUC under system -> DFS, I find the roots are still there. I remove them, and restart the two DFS services. Now I could create my V2 roots, and import the config that I had backed up in step 1 of the aforementioned technet article.

    Now all three servers have the appropriate registry keys under HKEY_LOCAL_MACHINE\Software\Microsoft\Dfs\Roots\DomainV2, and the drive mappings are all working.

    In regards to the intermittent mappings, I'm sure it was seen on some clients but not others due to my over-riding the referral ordering. I did this due to latency in copying large files. Five people in one department with their home drive targeting the same DFS share get assigned to DC2 and DC3. Another person in that department gets assigned to DC1, and copies a 2 GB file to it. IT gets a call when the rest of the department cannot see the file. (until it replicates) By over-riding referral ordering, and setting 1 server priority to a DFS folder, all users of that folder get the same server. But in the case of DC1 missing the reg key listing the DFS root structures (yes they showed in the DFS GUI), anyone with that had DC1 as the preference would not map to the DFS share.

    Funny thing is, there were no errors I could find on the affected clients or in the DFS logs on the servers.


    Wednesday, July 18, 2012 8:24 PM

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  • Thank you for the sharing!

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    Saturday, July 21, 2012 7:14 AM