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Secondary Dns server showing very high latency RRS feed

  • Question

  • Environment Description:

    I am having 10 dc in my environment , all having active directory integrated dns.

    Mainly 4 dns servers are used.

    Named as  A , B , C ,D

    We are having approx 20k plus clients and more than 95% clients are having server A as primary/ preffered dns server and B as their secondary/ alternate dns server. Rest 5% are having combination of A B C & D as their primary and secondary servers.

    Issue:

    The problem started few days back , on one fine day server A started giving very high latency, resulting in very frequent RTO and latency of upto 3000 ms, during troubleshooting when we made server B offline , server A started working fine with no latency .

    From that day whenever we made our server B online, server  A immediately starts giving latency and RTO.

    On few days situation is reversed also , that is on bringing server B online server B starts giving latency and rto.

    We tried disabling dns service of server B , so that no dns query is recieved by the server , but it is of no help.

    During night ( minimum load scenario) both server woks fine.

    Rest all dns serves are working fine , but server A and server B are having trouble working together.

    Please suggest the solution.


    • Edited by Deepak2809 Friday, December 30, 2016 2:42 PM
    Friday, December 30, 2016 10:09 AM

All replies

  • Hi Deepak,

    >>From that day whenever we made our server B online, server  A immediately starts giving latency and RTO.

    Please catch traffic of DNS server to check which steps expend much time to query by using Network monitor.

    Here is information about network monitor download for you reference:

    https://www.microsoft.com/en-us/download/details.aspx?id=4865

    Best Regards

    John


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    Monday, January 2, 2017 5:22 AM
  • I have already done that, lots of queries are coming from client for adobe update.

    I have also checked the same with wireshark tool, but still i am nor able to understand if one server is able to handle all yhe queries then why it starts giving latency when other one is made online, while the other one is only the alternate dns server in all clients.

    Tuesday, January 3, 2017 7:41 AM
  • Hi John,

    I have reinstalled OS on DNS server , at present neither AD nor DNS is configured on that server , but still on bringing it online , my another dns server starts giving latency

    No clues 

    Wednesday, January 4, 2017 4:43 AM
  • Hi Deepak,

    Have you tried to configure zone transfer between these DNS servers?

    If yes, Please disable it and try again.

    Best Regards

    John


    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Wednesday, January 4, 2017 7:27 AM
  • if server B is offline then when it comes online it will need to resume AD replication. 

    This may be the extra load you see on the other dc?

    Wednesday, January 4, 2017 8:18 AM