AlwaysON on one Node

  • Hi friends,

    Is it possible to configure ALwaysON with two instances on one node ?One of them to be Read-Write and other to be Read-Only. Any document reference link as steps would be great.Newbie on AlwaysON.Thank you in advance.

    Thanks and Regards

     

    Arshad

  • No - it isn't possible.  You must setup a Windows Server Failover Cluster - and a replica must reside on a different node in the same WSFC (with a few exceptions that don't matter here).

    https://docs.microsoft.com/en-us/sql/database-engine/availability-groups/windows/failover-clustering-and-always-on-availability-groups-sql-server?view=sql-server-ver15

    Jeffrey Williams
    Problems are opportunities brilliantly disguised as insurmountable obstacles.

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

  • Thanks Jeff,

    So "2 Nodes" is the minimum and WFC configured. Btw, as the replica has to be Read-Only, am I right in understanding that I must have and Active/Active WFC ? Big Thank You!

    Regards...Arshad

  • You can do a read scale AOAG without the need for a cluster.  You get no HADR features but if it’s just for reporting read scale is ample and you don’t have to manage the cluster element.

    AOAG clusters are always active active although that terminology is usually reserved for FCI’s not AOAG.

  • Ant-Green wrote:

    You can do a read scale AOAG without the need for a cluster.  You get no HADR features but if it’s just for reporting read scale is ample and you don’t have to manage the cluster element.

    AOAG clusters are always active active although that terminology is usually reserved for FCI’s not AOAG.

    active/active is inaccurate - even for FCI's.  You can have a multi-instance FCI where you have 2 or more instances hosted on 2 or more nodes in the cluster, but that still isn't active/active.

    A true active/active cluster isn't possible in Windows - and was utilized, as far as I know - only on DEC/ALPHA hardware with VMS and was a true shared everything cluster.

    Jeffrey Williams
    Problems are opportunities brilliantly disguised as insurmountable obstacles.

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

  • Thanks Jeff , that's so true.

  • Hi Ant Green,

    I could set up a read scale AOAG...Thank you !

     

    Rgds

    Arshad

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