DFS questions relating to SIS, VSS, Quotas and more

Discussion in 'File Systems' started by Barkley Bees, Dec 1, 2008.

  1. Barkley Bees

    Barkley Bees Guest

    I will be deploying two servers at two different offices (80 Mbps dedicated
    connectivity between offices). Both server builds are identical (Dell head
    servers and DAS enclosures) and will be installed with "Storage Server 2003
    R2 SP2 64-bit". These will be used purely for storing user folders (~1500
    users) which will be configured in Active Directory (Home Folder drive
    letter) for each user. The directory structure on the server will be simple:

    E:\USERS\username\ (USERS will be the shared folder with each username
    restricted by NTFS so only the user, SYSTEM and administrator accounts have
    access to his/her own folder).

    The plan is for "Server_A" to be the main server and "Server_B" to be the
    backup server in the event of a primary failure. We plan to use the updated
    DFS included with R2 to replicate the Users folder data to Server_B. In the
    event of a failure users would fail over to Server_B (using DFS namespaces).

    Some questions I hope you folks may be able to answer for me regarding
    DFS-R:

    1) Are there any issues with using VSS and DFS together? Will the VSS data
    be replicated across to "Server_B" as well and would VSS need to be enabled
    on this server also?

    2) Is it possible to use Single Instance Storage (SIS -natively available in
    Storage Server 2003 R2) with DFS? If it does the common store (in the root
    dir) need to get replicated across or do you simply enable SIS on the second
    server as well?

    3) Would it be better to configure DFS to replicate the "Users" folder or
    the actual root drive "E:\" as it will only be used for the users folders?

    4) Do the NTFS and share settings get replicated across also (I assume so)?

    5) I will be implementing quotas on the user folders using the "File Server
    Resource Manager" in R2. How would these Quotas be affected with DFS at the
    target server? Would they get carried over or would they need to be manually
    set on Server_B?

    6) All clients will be Windows XP SP2, so is it recommended to use the
    "Client failback" hotfix [WindowsXP-KB898900-v2-x86-ENU.exe
    (http://go.microsoft.com/fwlink/?LinkId=53202)] so that user computers can
    revert back to the original server once it is back online?

    7) In the event that Server_A is down and users are accessing and editing
    their files on Server_B, what happens when Server_A comes back online and
    clients revert back to it? The files they have edited on Server_B would not
    be available on Server_A since it was down when the files were changed My
    initial plan was for DFS to replicate one way, from Server_A to Server_B but
    taking this situation into consideration I realize this strategy is not
    sufficent. What is the recommended way to implement DFS Replication in this
    case?

    8) If I add Server_A and Server_B to the same namespace, can I ensure that
    users only go to "Server_A" to access files (given that it is up and
    available)?

    *note: our DCs are running Server 2003 SP1but I made the necessary AD schema
    update (adprep.exe /forestprep) to support the update R2 version of DFS

    Appreciate any feedback or advice that any of you may be able to offer on
    the above questions. Thanks very much.
     
    Barkley Bees, Dec 1, 2008
    #1
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  2. Barkley Bees

    HAL07 Guest

    1) VSS data will only affect the current server you are connected to. However as the data are synced, VSS will pick this up at
    both servers.
    2) dunno
    3) I would recommend to sync using folders. E.g. E:\DFS\Users
    4) NTFS settings are replicated. Shares are generated during setup of DFS Management (Use wizard) and is a one-time job. Future
    Shares needs to be implemented manually on both servers (as far as I know)
    5) dunno
    6) I think I would recommend a logoff/logon if it's a home folder, since home folders are handled specially in Windows. They are
    mounted as homedir and can sometimes be locked by system files, thus it can be impossible to unmount and remount on-the-fly.
    7) DFS replication should be both ways.
    8) You should only publish the replication group name for BOTH servers. The Windows DFS client will automatically choose the
    closest server.

    --
    -- HAL07, Engineering Services, Norway

     
    HAL07, Dec 1, 2008
    #2
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  3. Barkley Bees

    DaveMills Guest

    Quotas do not sit nicely with DFSR. You can run into real problems when one
    folder is out of space and the other is not. Remember that tmp files etc. are
    not replicated. This means that ServerA will have more data in each folder than
    ServerB. After Failure ServerA restarts and it will replicate all changed files
    from B to A but where somebody hits their quota on B the DFSR will fail because
    if cannot replicate the data back to A due to the presence of the additional TMP
    files.

    I am considering how to implement this next year and at the moment my plan it
    to have quotas on A and not B and also to have the referrals to B disabled. In a
    failure I can enable the referrals to B. When server A is fixed I can switch the
    quotas from Hard to Soft and allow replication to bring B up to date. Then
    disable referrals to B and finally return the quotas from Soft to Hard. Of
    course I have not tried this yet but it is a plan arising out of the failure I
    saw at my previous employment.

    Another point is that you must make sure the staging folder are outside the
    quota space. This is going to be much easier if you replicate "users" but only
    have quotas on the users\%username% folders.






     
    DaveMills, Dec 2, 2008
    #3
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