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Is it possible to downgrade functional level of a cluster ? RRS feed

  • Question

  • Hello Experts,

    Is it possible to join Node with OS 2012 R2 to a installed and running cluster with OS 2016 ?

    I know i can add a node that runs a more recent version of the Windows operating system into a cluster of nodes that run a previous version. but can i do the opposite ?

    Thanks in Advance.

    Thursday, July 26, 2018 10:15 AM

All replies

  • Hello,

    If your failover cluster is at Windows Server 2016 functional level, there is no option to downgrade or add Windows Servers 2012 R2 nodes to the cluster. 

    You can check your cluster functional level with

    Get-Cluster | Select ClusterFunctionalLevel  

    Value 8 = Windows Server 2012 R2

    Value 9 = Windows Server 2016


    Microsoft Certified Professional

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    • Proposed as answer by Tim CerlingMVP Thursday, July 26, 2018 11:57 AM
    Thursday, July 26, 2018 11:04 AM
  • "I know i can add a node that runs a more recent version of the Windows operating system into a cluster of nodes that run a previous version"

    This was something that was added in 2016, so it is available only to add 2016 to a 2012 R2 cluster.  Of course, similar capability will exist for 2019, but it is not yet released so we can't talk to final details on 2019 capabilities.


    tim

    Thursday, July 26, 2018 11:59 AM
  • Hello Experts,

    Is it possible to join Node with OS 2012 R2 to a installed and running cluster with OS 2016 ?

    ===> No, if the functional level of the Cluster is @ 2016.

    I know i can add a node that runs a more recent version of the Windows operating system into a cluster of nodes that run a previous version.

    ===> Not true unless its Win 2012 R2 -> Win 2016.

    but can i do the opposite ?

    ===> Big NO.

    Thanks in Advance.



    yup

    Friday, August 3, 2018 3:46 PM
  • The purpose of a mixed WSFC is for upgrade only - specifically rolling upgrades - and not to run in a normal day-to-day state. As others have pointed out, you cannot add a downlevel server as a node to a later version of Windows Server in a WSFC configuration.

    Allan Hirt Microsoft High Availablity and SQL Server MVP, VMware vExpert Twitter: @SQLHA Blog: http://www.sqlha.com/blog


    Tuesday, August 7, 2018 7:11 PM