WSFC : Manual or automatic failover? That is the question!

During the night, you receive an alert concerning your SQL Server failover cluster or your availability groups and you’re in panic mode because the message displayed is : a failover has occured .. see the log for more details …

So keep quiet and after connecting to your environment you are not able to find anything … What was happen? Maybe someone has triggered manually a failover and you are not aware of it. I’m sure by reading the previous sentences many of you will recognize but the real question is: is it possible with a Windows failover cluster to disting a manual failover from an automatic failover?

The answer is yes and one way to find out the response is to take a look at the cluster.log. In fact, you have an record entry that clearly identifies a manual failover of resources:

[RCM] rcm::RcmApi::MoveGroup: (, 1, 0, MoveType::Manual )

As a reminder, this is the resource control monitor [RCM] that is responsible to perform actions according to the state of a resource. In fact, when you trigger a manual failover the MoveGroup API is called with a identified parameter MoveType::Manual

Let’s me know if you find a other way to discover a manual failover

Happy failover (or not) !

By David Barbarin