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Availability Group

  • March 12, 2015 at 2:22 pm

    #315651

    I have a 2-node Windows Cluster and File Share Witness with an availability group. The cluster is set to sync and auto failover. I'm using SQL 2014 and Windows 2012R2. I'm trying to understand the steps to apply Windows Updates that require a restart. Are the steps something like this where ServerA is the primary replica and ServerB is the secondary replica.

    Apply updates to ServerB.

    Restart ServerB.

    Fail ServerA availability group to ServerB using ALTER AVAILABILITY GROUP MyAvailGroup FAILOVER;. Server B is now the primary.

    Apply updates to ServerA.

    Restart ServerA.

    Fail ServerB availability group to ServerA using ALTER AVAILABILITY GROUP MyAvailGroup FAILOVER;. Server A is now the primary.

    What I don't understand is where Drain Roles on the Failover Cluster Manager fits in?

  • March 12, 2015 at 3:31 pm

    #1783732

    Hi Terrie,

    I hope that answers your question

    AlwaysOn Availability Groups relies on the Windows Failover Clustering (WSFC) cluster to monitor and manage the current roles of the availability replicas that belong to a given availability group and to determine how a failover event affects the availability replicas. A WSFC resource group is created for every availability group that you create. The WSFC cluster monitors this resource group to evaluate the health of the primary replica.

    from: https://msdn.microsoft.com/en-us/library/ff929171.aspx

    Also the WSFC switch your Listener to the new primary Server.

  • March 12, 2015 at 9:45 pm

    #1783764

    What I don't understand is do I need to Drain the role of ServerA before I run ALTER AVAILABILITY GROUP MyAvailGroup FAILOVER?

    This link explains how to restart a node in a cluster.

    http://blogs.msdn.com/b/clustering/archive/2013/08/23/10443912.aspx

    This link explains how to perform a planned manual failover of the Availability Group and makes no mention of Draining the roles.

    https://msdn.microsoft.com/en-us/library/hh231018.aspx

  • March 13, 2015 at 9:01 am

    #1783914

    by failing over the AG you are draining the node of any roles it holds

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    "Ya can't make an omelette without breaking just a few eggs" 😉

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