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Long delays in Windows Explorer operations and logins when one domain controller is offline

    Question

  • Hello

    We have a site with two domain controllers and I've noticed that when one of the two DCs is down for maintenance, any file operations involving Windows Explorer on any domain members, including third-party applications, is horrifically slow to the point of being unusable. I've also noticed a similar delay in attempting to log in to clients when this domain controller is offline. We also have set folder redirection to a share on this server in group policy, I'm not sure if that is related or not. I'm trying to build as much redundancy and fault-tolerance in to this network as possible and it seems like this is a very serious weak point. Does anyone have any ideas why this behavior is occurring and what I could to do mitigate it?

    Thanks,

    Jared

    Wednesday, May 18, 2016 3:03 PM

Answers

  • The Folder Redirection is entirely related. When a user logs on and the server is offline, FR will try each redirected path and wait for it to error out. You can get the timings from the event log > Application on a user's pc.

    Regarding the DC that is offline, which FSMO roles does it hold and what is your DC replication/topology health?

    Wednesday, May 18, 2016 7:08 PM
  • Hi,
    Generally, if FSMO roles are unavailable, it will not generate immediate impact on client, except for PDC.
    Here is an article regarding responding to operations master failures, you could see details from it:
    https://technet.microsoft.com/en-sg/library/cc737648(v=ws.10).aspx
    Regards,
    Wendy

    Please remember to mark the replies as answers if they help and un-mark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, May 23, 2016 2:08 AM
    Moderator
  • Hi Jared,

    I just want to bring this back to what zxxzxx said: folder redirection will have everything to do with it - particularly if the AppData folder is being redirected.

    The only FSMO role that will have something even resembling an immediate impact is the PDC role, however, that only has an immediate impact on certain tasks such as those relating to password management.

    I'm not sure what you define as maintenance, but if it's something like half an hour here or there to apply some Windows updates then that's not a reason to be transferring FSMO roles. If it's going to be a day, on the other hand, then sure, you might want to transfer the hosted FSMO roles before dropping the server. But this is just general advice and not likely to be overly related to your problem.

    One other point to consider is the impact on name resolution if this is the primary DNS server. It's isn't a major influencer and alone wouldn't produce the slowness you're describing, however, it can make enough of a difference to some processes that the user will notice the impact of its unavailability from time to time.

    With respect to mitigation - at least of the folder redirection, you'd need to look at Failover Clustering Services (not DFS), but before you do that, you should break the file hosting function out and onto a dedicated file server host as there's no reason to be running FCS on a domain controller.

    Cheers,
    Lain

    Monday, May 23, 2016 2:23 AM

All replies

  • The Folder Redirection is entirely related. When a user logs on and the server is offline, FR will try each redirected path and wait for it to error out. You can get the timings from the event log > Application on a user's pc.

    Regarding the DC that is offline, which FSMO roles does it hold and what is your DC replication/topology health?

    Wednesday, May 18, 2016 7:08 PM
  • Hi Jared,
    Regarding to mitigate slow log in, I would suggest you take a look the following blog to have a try as it suggested:
    https://blogs.technet.microsoft.com/askds/2009/09/23/so-you-have-a-slow-logon-part-1/
    And if the server is holding FSMO roles and is going to be down for long periods of time, then you should transfer FSMO roles to the other domain controllers.

    Regards,
    Wendy


    Please remember to mark the replies as answers if they help and un-mark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Thursday, May 19, 2016 8:48 AM
    Moderator
  • The server holds the PDC emulator role, schema master and domain naming operation master but not the other two roles. AD replication health is fine, at least according to logs and the AD Replication Status Tool.

    There are over a dozen laptops on our domain that are used offsite on a regular basis where they don't have access to the share holding the FR subfolders and they work fine. I will see if there is a time when I can take the server offline for a little while and check logs on the client side to see what if anything is recorded.

    Thanks!

    Thursday, May 19, 2016 3:13 PM
  • Thanks, I'll go the process that they outline in that document. The server holds some but not all of the FSMO roles; I'm not planning on taking this sever offline for any length of time, just working on disaster recovery preparation. It's odd, the clients are almost acting like they are trying and failing to connect to a domain controller, even though there is still one online. Would not being able to access the server holding one of those FSMO roles cause this behavior?
    Thursday, May 19, 2016 3:17 PM
  • Hi,
    Generally, if FSMO roles are unavailable, it will not generate immediate impact on client, except for PDC.
    Here is an article regarding responding to operations master failures, you could see details from it:
    https://technet.microsoft.com/en-sg/library/cc737648(v=ws.10).aspx
    Regards,
    Wendy

    Please remember to mark the replies as answers if they help and un-mark them if they provide no help. If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, May 23, 2016 2:08 AM
    Moderator
  • Hi Jared,

    I just want to bring this back to what zxxzxx said: folder redirection will have everything to do with it - particularly if the AppData folder is being redirected.

    The only FSMO role that will have something even resembling an immediate impact is the PDC role, however, that only has an immediate impact on certain tasks such as those relating to password management.

    I'm not sure what you define as maintenance, but if it's something like half an hour here or there to apply some Windows updates then that's not a reason to be transferring FSMO roles. If it's going to be a day, on the other hand, then sure, you might want to transfer the hosted FSMO roles before dropping the server. But this is just general advice and not likely to be overly related to your problem.

    One other point to consider is the impact on name resolution if this is the primary DNS server. It's isn't a major influencer and alone wouldn't produce the slowness you're describing, however, it can make enough of a difference to some processes that the user will notice the impact of its unavailability from time to time.

    With respect to mitigation - at least of the folder redirection, you'd need to look at Failover Clustering Services (not DFS), but before you do that, you should break the file hosting function out and onto a dedicated file server host as there's no reason to be running FCS on a domain controller.

    Cheers,
    Lain

    Monday, May 23, 2016 2:23 AM