DFS concern about FSMO roles

Discussion in 'File Systems' started by steve, Mar 14, 2006.

  1. steve

    steve Guest

    hi,
    i setup DFS for file sharing redundancy purpose.

    In my senario, i installed DFS on 2 domain controller. Firstly, i installed
    DFS on DC1 and DC2 as root target. so file sharing on the clients will swing
    between these 2 DCs. My thought is DC1 is holding the FSMO roles. IF DC1
    fails, my DFS will be totally Offline, instead of failover to DC2. Because AD
    is stored in AD, file sharing will have problems when FSMO roles server is
    down. IS my understanding correct?
    It looks like a single point of failure too. and no matter where my FSMO is
    holding at any DC.

    pls advice

    steve
     
    steve, Mar 14, 2006
    #1
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  2. Hi,

    DFS is totally dependent on de PDC emulator. So if the PDC goes down DFS
    will run but you will not be able to manage it anymore!
    So the PDC is the single point of failure!

    Best thing to do is implemmenting a third DC that holds the PDC role but
    does not hold any DFS function such as root targets etc.

    greets,
    Marco
     
    Marco (MCP, MCSA, MCSA Messaging, MCSE), Mar 15, 2006
    #2
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  3. steve

    steve Guest

    Hi Marco,

    But i have tested if the PDC role is down... the DFS shared on the client is
    down too meaning they cant access the DFS mapped drive.

    Even the 3rd DC, as u mention DFS is totally dependent on de PDC emulator,
    if this DC goes down, it will be the same, DFS shared on the client access
    will be denied, right?

    steve
     
    steve, Mar 15, 2006
    #3
  4. Hi,

    Point is that if the PDC goes down de clients still wil work with the other
    DC who also hold de DFS functions! So no harm wil be done to the connectivity
    of the shares.
    If the PDC and a DFS server goes down (low chance) than you will have a more
    serious problem on your network than the DFS not being available. :)

    In your situation: If the PDC goes offline the clients will look for the
    second root targets of the DFS root and/or links! To do that they will ask
    the PDC for an alternate path! If there is any! No PDC no "fail-over" for the
    client will be available.
    This is because the PDC-emulator holds the File Partition Table for the
    entire Domain DFS.

    Hope this answer satisfies your needs! Else ask!

    Greets,
    Marco
     
    Marco (MCP, MCSA, MCSA Messaging, MCSE), Mar 15, 2006
    #4
  5. steve

    steve Guest

    Hi Marco,
    Pardon me, im still confuse about your remarks below.
    #Here u mean that even PDC is down, clients can still connect to dfs shared.
    Meaning clients will connect to another dfs server. Right?
    #Your sentence is straight-forward. PDC is down, No DFS at all.

    So what is what? I want to know when PDC is down,
    1) will the DFS failover to another dfs server?
    2) Will my clients get dis-connected from the DFS file share?

    Thanks for your patience,
    steve
     
    steve, Mar 15, 2006
    #5
  6. Hi Steve,

    Forgive my English, it's not my native language. I am from Holland!
    Situation:
    1 DC - FSMO roles (PDC schema etc)
    2 DC's DFS configured!

    So if 1 goes down the 2 DC's with DFS wil still be working and clients wil
    not notice this, because the are already connected to the DFS root! DFS root
    is online even if PDC is down! (Know this from working experience)

    To answer your questions:
    1) will the DFS failover to another dfs server?
    Nope because PDC is down! But the two "DFS" servers are still
    operational and servicing client request.

    2) Will my clients get dis-connected from the DFS file share?
    Nope because the "DFS" servers are still operational.

    In both situations if you have 3 DC's but the "PDC role holder has no DFS
    configured on it". You cannot configure or manage the DFS via MMC-snapin, but
    the DFS on the 2 working "DFS" servers wil just be fine and service client
    requests!

    Only if the PDC and one DFS server goes down (not likely to happen) you wil
    lose client connectivity, because the File Partition Table isn't available!

    Hope it is clearer now!

    greetings,
    Marco
     
    Marco (MCP, MCSA, MCSA Messaging, MCSE), Mar 15, 2006
    #6
  7. steve

    steve Guest

    Hi Marco,

    Thanks for yor explanation.
    In my senario
    DC1 - DFS server, 5 FSMO roles
    DC2 - DFS server

    When i shutdown DC1, all my clients could not access to DFS shared. it does
    not failed over to the online DC2's DFS.

    then i try shutdown DC2, those clients which connected to DC2 DFS at that
    time, will failover to DC1 DFS.

    Is my result's behaviour correct? I guess so, if my understanding to your
    explanation is correct.

    So the point is whenever if a DFS is unavailable, the client will query for
    PDC for another DFS. if PDC is down.. no failover.
    However, if PDC is not the same box as DFS server, If PDC is down, client
    will still remain connected because DFS is not affected.
    Bingo??

    But if i host all FSMO on another DC without DFS, when this DC is down..
    Isn't the whole domain will be affect.. example: domain users may not able to
    login, users may not able to access domain shares folder. am i rite??

    cheers,
    steve
     
    steve, Mar 15, 2006
    #7
  8. BINGO!!!!!!!!

    If you have a DC with all the 5 FSMO roles and it goes down! You still wil
    have a functioning Domain (Not fully functioning.)

    Users can still access resources and logon to another DC.
    You wil eventually not be able to create new users, create new shares or set
    NTFS permissions etc.

    But in an event of a FSMO role holder failing you are always on Alertstatus
    1 and you will try to fix the problem as soon as possible anyway!!!

    good luck!!!

    Marco
     
    Marco (MCP, MCSA, MCSA Messaging, MCSE), Mar 15, 2006
    #8
  9. If you'd like more detail about how DFS works, check out the DFS Technical
    Reference at
    http://technet2.microsoft.com/WindowsServer/en/Library/a9096e88-1634-4da6-b820-537341d349061033.mspx.
    You can search for "PDC" to learn more about the role PDC plays in DFS. The
    PDC is where all changes to the namespace are made, and then the root
    servers poll this server to obtain the latest namespace metadata. If the PDC
    is down, you cannot make changes to the namespace. However, the namespace
    continues to function.
     
    Jill Zoeller [MSFT], Mar 15, 2006
    #9
  10. steve

    steve Guest

    Hi Marco,

    Sorry to bug u again. i have another thng to ask.

    2 domain controller with dfs.
    DC1 - DFS with FSMO roles
    DC2 - DFS

    IF DC1 is dead
    says got a user just walk in office and started to login to domain. Will the
    dfs shares work on his machine? will he get to refer to the online DC2 DFS?

    My point is my trying to know if my FSMO is down, whether PDC is at DFS
    server or, when a new user walk-in office and start to login domain. Can he
    access to another online DC's dfs ??


    thanks
    steve
     
    steve, Mar 16, 2006
    #10
  11. steve

    steve Guest

    Hi Marco,

    Sorry to bug u again. i have another thing to ask.

    2 domain controller with dfs.
    DC1 - DFS with FSMO roles
    DC2 - DFS

    IF DC1 is dead
    says got a user just walk in office and started to login to domain. Will the
    dfs shares work on his machine? will he get to refer to the online DC2 DFS?
    i understand that if the current users were connected to DC1 dfs, they will
    not be able to 'swing' to dc2 dfs as the PDC is down.


    My point is my trying to know if my FSMO is down, whether PDC is at DFS
    server or, when a new user walk-in office and start to login domain. Can he
    access to another online DC's dfs ??


    thanks
     
    steve, Mar 19, 2006
    #11
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