AlwaysOn for HA/DR

  • Hi All,

    We are trying to find best HA/DR solution for our (SQL Sever 2008R2 STD )PRD server.We were thinking to go with Database Mirroring or Failover Clustering.But since Mirroring is not available in newer versions we decided to upgrade to 2014 and go with Always On. We are looking for ALMOST 0 downtime.Any suggestions?

    thank you

  • Does SQL Server HA has 0 down solution?

    Even in SQL Server 2014 AlwaysON, then failover to secondary node, the application side need to reconnect.

  • If you setup always on with a listener you will have a small amount of downtime (milliseconds) when the secondary becomes primary. Most of the time it's not even noticeable.

  • Barcelona10 (11/5/2015)


    Hi All,

    We are trying to find best HA/DR solution for our (SQL Sever 2008R2 STD )PRD server.We were thinking to go with Database Mirroring or Failover Clustering.But since Mirroring is not available in newer versions we decided to upgrade to 2014 and go with Always On. We are looking for ALMOST 0 downtime.Any suggestions?

    thank you

    mirroring is still there in 2014.

    you're looking at mirroring, FCIs and AGs. What is it you are trying to mitigate, as they all do something different

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  • daniel.hughes 66721 (11/6/2015)


    If you setup always on with a listener you will have a small amount of downtime (milliseconds) when the secondary becomes primary. Most of the time it's not even noticeable.

    The failover from a SQL perspective will barely be noticeable, but all applications with open transactions will return errors and will need to re-establish their sessions.

  • Mirroring still exists. Also, MS cannot remove mirroring unless they have a version of HA which will replace Mirroring.

    So Mirroring will always be there, albeit, as a poor man's DR solution.

    Windows failover provides high availability but not Fault tolerance.

    So the question is, what are your requirements? HA or High fault tolerance?

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  • MadAdmin (11/10/2015)


    MS cannot remove mirroring unless they have a version of HA which will replace Mirroring.

    Yep, it's called Basic Availability groups in SQL Server 2016

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