AlwayOn 2012 Avaiability Group Listener DNS resolving to DR Node

  • Hi,

    We are rolling out the use of Availability Group listeners to our SQL Server 2012 Environment which has a 2 node multi-subnet cluster. The Primary is R/W and the Secondary is a non-readable node that would be manually failed over to in a DR scenario

    I have set up the AGL and asked the sysadmins to create a DNS record in both subnets with fixed IP's.

    The issue I have having is that when I ask the app developers to connect to the databases using the AGL it is totally random whether the AGL resolves to the Primary or DR node - as a result that are having problems getting their apps to connect.

    I was thinking of asking the sys admins to remove the DNS record in the DR subnet and then add it back in should we need to fail over - but I was thinking there must be a better way.

    Would be great to hear from anyone who has the same setup,

    Cheers.

  • I ran into this issue and I believe we got around it by specifying 'MultiSubNetFailover=True' in the connection string when connecting to the listener.

  • Pending if your connection string level is recent enough that may not be possible and you will need to change RegisterAllProvidersIP to 0.

    http://blogs.msdn.com/b/alwaysonpro/archive/2014/06/03/connection-timeouts-in-multi-subnet-availability-group.aspx

    This will require DNS changes on failover*

  • Thanks so much for the feedback - it has solved my issue - I will patch the .net framework where I can so we can use the 'MultiSubNetFailover=True parameter and I have also gone through the steps in the link and can confirm all is OK since I have done that.

    Once again many thanks - this is a big win for me :w00t:

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