In this article we are going to explore how to configure an Availability Group between a clustered instance and a standalone instance, showing, step-by-step, how to setup a possible Disaster Recovery environment.
Introduced on SQL Server 2012, the Availability Groups brought the expectation to be an improved version of the database mirroring, which will be discontinued soon. The AlwaysOn Availability Groups was improved on SQL Server 2014, giving the capability of have more replicas, better troubleshooting possibilities and improving its availability. Comparing the Availability Groups with the database mirroring, in a very high level, we gained the possibility of have a listener to dynamically redirect the connection to the current active instance and also the capability of distribute the read workload between readable replicas. However, only the primary replica is able to write.
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