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Combing FailOver Cluster Instance with AlwaysOn Availability Group for DR

  • May 3, 2019 at 5:06 pm

    #3634471

    Hello Folks,

    I've a requirement to add AlwaysOn for DR on top of an existing FCI (Failover Cluster Instance). Please provide detailed steps on how to configure this. Any issues on this setup.

    Existing FCI - 2 Node Active-Passive (Physical Servers)

    Environment: SQL 2014 Enterprise / Windows Server 2012 R2

     

    Many thanks!

    • This topic was modified 5 years, 6 months ago by  SQL!$@w$0ME.

  • May 3, 2019 at 6:28 pm

    #3634542

    I can't provide 'detailed' steps - but I will provide an outline.  You will need to research for further details:

    1. Add the new DR node to the cluster - without shared storage.  Validate the cluster.
    2. Evict the new node from the cluster and install a standalone instance of SQL Server.  Patch to the same patch level as the FCI cluster instance.
    3. Add the node back into the cluster
    4. Setup your AOAG using the secondary instance on the new node

      1. If you want the clients to be able to connect automatically to the DR node - then you can setup a listener.  If you are going to setup the clients to connect from systems at the DR site you won't need the listener.
      2. If the DR node is close enough - you can use synchronous without automatic failover.  If it is not close enough - then you would set it up as asynchronous.

    5. Add databases to the AOAG

    There is nothing wrong with this configuration - but you do need to be aware of how the cluster fail over process works.  If you require automatic failover to the DR site if both local nodes are down then you will need to review how nodeweight is used to determine quorum for the cluster.  You will also need to consider a folder share that is accessible to both sites for quorum - as the DR node will be down if quorum cannot be maintained.  And - you will need to understand how the cluster determines which node priority for failovers.

    I personally don't want a failover to the DR site/server to happen automatically - I only want that to occur when the business has made the determination that the primary data center or servers cannot be brought back up in a reasonable amount of time.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • May 7, 2019 at 7:41 pm

    #3637353

    We have implemented AGs between two 2-node FCIs, as well as between a 2-node FCI and a standalone instance.  No real problems.  We generally like it.

    I don't think there is very much to setting this up, we pretty much treated it just like setting up an AG between two standalone instances.  FWIW we never evicted the node from the cluster prior to installing SQL.

  • May 7, 2019 at 8:51 pm

    #3637430

    Mike Good wrote:

    FWIW we never evicted the node from the cluster prior to installing SQL.

    The problem occurs when you utilize cluster shared volumes - the secondary node needs to have the same drive layout for the databases and SQL Server will not install as a standalone instance because those volumes are considered as part of the cluster even if they are not shared.

    The only way around that is to evict the node - install SQL Server - then add the node.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

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