AlwaysOn Availability Group Forced Failover: Under the Hood

In this walkthrough I will take you through one aspect of FCI + AG configuration: forced failover. We will simulate failure and force failover. And in the process we will have some … Data Loss. Does that not sound horrible! Relax! You should not worry too much , because in this case what we are…

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AlwaysOn Availability Groups Connectivity Cheat Sheet

Today we were discussing the AlwaysOn connectivity options, and the various combinations therein of Readable Secondary setting and the connection strings became very complex. So I have summarized all the possible outcomes in the pivot tables below. For convenience, we have two tables. The first table covers the cases when the Primary Replica is set…

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AlwaysOn Availability Groups Listener: connectivity details

Today in some discussions with my colleagues we were looking at the AlwaysOn Listener which allows SQL Server client applications to be abstracted from the details of the AlwaysOn Availability Group implementation. On the surface, The Listener essentially is a cluster resource pair – a Virtual IP and a Virtual Network Name. But on deeper…

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Error message: The target database (‘xyz’) is in an availability group and currently does not allow read only connections

Today while poking around the AlwaysOn Availability Groups feature I came across the above error when testing the read-only access routing configuration. That configuration allows connections with declared ReadOnly intent to be routed to one of the read-only secondary replicas. The configuration looked like this: 3-node Windows 2008 R2 Core cluster 3 instances of SQL…

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