2003 R2 DFS Namespace - first / last among all targets issue.

Discussion in 'File Systems' started by Barkley Bees, Feb 24, 2009.

  1. Barkley Bees

    Barkley Bees Guest

    I have two identical 2003 R2 servers set up with DFS Namespace and
    replication between them. I have a target folder published in the namespace
    with server A set as "First among all targets" and Server B "Last among all
    targets" (of course with "Override referral ordering" checked too). The
    servers have been in production for about 5 weeks now with no real issues
    but suddenly this past week I have noticed users showing up on server B when
    I look at the shared folder sessions and open files.

    I would have thought given the specified settings that users would only
    access server B if server A was down. Is this not the case and if not, is
    there any way I can make it as such? Appreciate any advice. Thanks.
     
    Barkley Bees, Feb 24, 2009
    #1
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  2. Hello Barkley,

    Are both targets in a single AD site? The target prioritazation you just
    mention will work only if your targets are in a single AD site with one
    physical location. If both are in the same physical location, then you may
    want ot check your Referrals ordering method to make sure you select "Lowest
    Cost" and not "Random Order". Also, be aware that DFS targets for a single
    site can be randomly selected highest or lowest and on remote site targets
    can be ordered using AD site link cost or randomly as well.

    Isaac
     
    Isaac Oben [MCITP,MCSE], Feb 24, 2009
    #2
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  3. Barkley Bees

    Barkley Bees Guest

    Hi Isaac,

    Thanks for your reply. In answer to your questions:

    -Both targets are in a single AD site.
    -Two physical locations with a dedicated 100MB link between them.
    -Referrals ordering method in the DFS Root is set to "Lowest cost" (target
    folder inheriting from root).

    Server A gets around 500-600 user sessions at peak hours while Server B gets
    only 10-15. Also the users connecting to server B are connecting from the
    physical location where Server A is.

    Another strange aspect about it if I may: we have two Metaframe servers (out
    of scope for this forum) that are in a load balancing configuration. Users
    connected to Meta Server X are only accessing the DFS target on Server A
    while users connected to Meta Y are only accessing the target on Server B.

    DFS Server A, Meta Server X and Meta Server Y are in one physical location
    on the same VLAN. DFS Server B is at another physical location but on the
    same LAN (different VLAN) with a dedication 100MB link. Only one AD site
    exists.

    DFS Root is set with Ordering method: Lowest cost
    Name space Servers is set to "override referral ordering" with Target
    priority set as:
    Server A - First among all targets, Server B - Last among all targets.



     
    Barkley Bees, Feb 25, 2009
    #3
  4. Hello Barkley,
    Are ServerA and ServerB Domain Controller? If so try to edit registry key
    for ServerA to include
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dfs
    "PreferLogonDC" dword:value of 1. This should force users to look for dfs
    first from ServerA. Let us know if this solved your problem if not then we
    might have to look into your subnets

    --
    Isaac Oben [MCTIP, MCSE]
     
    Isaac Oben [MCITP,MCSE], Feb 25, 2009
    #4
  5. Barkley Bees

    Barkley Bees Guest

    Unfortunately not...both server A and B are simple dedicated File Servers
    using DFS namespaces and replication (Windows Storage Server 2003 R2 x64) .
    They are, though, in different subnets.

     
    Barkley Bees, Feb 26, 2009
    #5
  6. Barkley,

    The suggestion I might say is that of using a script, maybe logon script, to
    force users to use DFS shares based on their subnets.

    Isaac

    --
    Isaac Oben [MCTIP, MCSE]
     
    Isaac Oben [MCITP,MCSE], Feb 26, 2009
    #6
  7. --
    Isaac Oben [MCTIP, MCSE]
     
    Isaac Oben [MCITP,MCSE], Feb 26, 2009
    #7
  8. Barkley Bees

    DaveMills Guest

    I have seen this too. I think it may be due to loading but have never verified
    this. If Server A is very busy then the client may switch to ServerB believing
    the late response is due to ServerA being down. This is clearly a possibility as
    part of the design of DFS. The issue is how long to wait for a response before
    deciding that a server is not available and using the alternate server.


     
    DaveMills, Mar 1, 2009
    #8
  9. Barkley Bees

    Barkley Bees Guest

    This is what I had initially thought but after having watched it for a few
    weeks, I can see that it seems to be the same 3-4 users who go to this
    server over and over.

    Btw, after rebooting the secondary DFS server this morning I could see that
    users from both Metaframe servers were now going to the primary server.
    I had noticed, from looking around, that the Metaframe servers didn't have
    any WINS addresses configured and only one of our internal DNS servers. So,
    I corrected the settings on them both. I don't know, though, if this can
    attributed to the strangeness I mentioned before where users from "Meta
    Server X" went to "DFS Server A" and "Meta Server Y" went to "DFS Server B".
    I will be monitoring it and update if any change.

    Just thinking aloud here but if I 100% want users to only go to the primary
    server (even if there is a failure), could I create another site and put the
    secondary server in it and specify for users to only go to the server in the
    same site? Really what we want is for ALL users to only go to the primary
    server and in the event of a failure, use DFS-R to replicate the files back
    from the secondary server to the primary after it has recovered (if
    necessary - ie: total hardware failure).

     
    Barkley Bees, Mar 6, 2009
    #9
  10. Barkley Bees

    DaveMills Guest

    Remember you do not need to have DFS name space for DFSR to function. My plan is
    to have home folders on serverA and replication using DFSR to serverB. I will
    have the DFS namespace configured but I will disable the link to serverB. In the
    event of a failure of serverA I can disable the link to serverA and enable the
    link to serverB. When serverA is fixed I can change all quotas to soft quotas,
    avoiding the replication from hitting hard quota limits. A after replication is
    complete enable the link to serverA and disable the link to serverB again. Once
    replication has fully completed I can report on "over quota" users and restore
    hard quotas again.
     
    DaveMills, Mar 10, 2009
    #10
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