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Synchronizing with Multiple Servers

Owned by Aliaksei Shautsou (Deactivated)
Last updated: May 19, 2017 by Olga Nekrutkina
2 min read

Because a Grid member can manage multiple Microsoft servers, it could potentially manage multiple servers assigned to the same zone. For example, a Grid member could manage a Microsoft server that is the primary server of a zone and one or more Microsoft servers that are secondary servers of the same zone. It could also manage multiple Microsoft servers that are secondary servers for the same zone.
If a Grid member manages the primary server and at least one secondary server of a zone, the Grid member always synchronizes DNS data with the primary server only. It never synchronizes data with the secondary server, even if the primary server fails.
If a Grid member manages several Microsoft servers that are secondary servers of the same zone, it synchronizes DNS data as follows:

  • If each Microsoft server is assigned to a different DNS view, the Grid member synchronizes data with each one.
  • If the Microsoft servers are synchronized to the same DNS view, the Grid member selects a principal server for synchronization purposes, as follows:
    • The first Microsoft server that is assigned as the DNS secondary server is designated principal server.
    • If the secondary servers are managed in read-only and read/write modes, the Grid member always selects a server that is managed in read/write mode.
    • If a Microsoft server fails three successive synchronizations, it loses its principal server status. The Grid Master checks the date that each server last became a principal server and selects the server that has not been the designated principal server the longest.

Note that a Grid member could fail to synchronize with a Microsoft server due to errors, such as a disabled account or an expired password. In these situations, the failure count is reset and is not increased. This prevents the Microsoft server from losing its master status to another Microsoft server that could experience the same errors.
When a zone is served by multiple Microsoft servers, the MS Sync Server column of the Zones tab shows which Microsoft server is actually performing the synchronization of that zone with the Grid.