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Internal mechanism of SQL Server Always On fail over Process

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Hi,
Can you explain your question in more details and also specify which part of SQL Server Always On offering you are thinking of (Always On Failover Cluster Instances or Always On availability groups)?
Always On Failover Cluster Instances leverages Windows Server Failover Clustering (WSFC) functionality to provide local high availability through redundancy at the server-instance level—a failover cluster instance (FCI). The FCI provides failover from one WSFC node to another if the current node becomes unavailable. For more information, please refer to the documents from Always On Failover Cluster Instances (SQL Server).
For an Always On availability group, it supports a replicated environment for a discrete set of user databases. A high availability group is a group of databases that fail over together. There are three forms of failover exist in AG: automatic failover (without data loss), planned manual failover (without data loss), and forced manual failover (with possible data loss), typically called forced failover. About how these three forms of failover work, please refer to the document from Failover and Failover Modes (Always On Availability Groups).Best Regards
Puzzle
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https://blogs.msdn.microsoft.com/psssql/2013/04/22/how-it-works-always-onwhen-is-my-secondary-failover-ready/
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I would like to know the Cluster fail over internal mechanism.
- Merged by Shanky_621MVP Wednesday, July 10, 2019 7:20 AM duplicate
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Hello Bhanu,
Refer below articles for more details,
https://blogs.technet.microsoft.com/rob/2008/05/07/windows-failover-clustering-overview/
https://docs.microsoft.com/en-us/sql/sql-server/failover-clusters/windows/windows-server-failover-clustering-wsfc-with-sql-server?view=sql-server-2017#AlwaysOnWsfcHealth
https://docs.microsoft.com/en-us/windows-server/storage/storage-spaces/understand-quorum
Regards;
Vivek Janakiraman- Proposed as answer by Teige GaoMicrosoft contingent staff, Moderator Wednesday, November 28, 2018 6:59 AM
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Hi Chen,
I need Internal mechanism of Always On availability groups fail-over.
could you please explain stepwise..
Please read online there are lot of documents explaining this. Below link has lot of documents explaining the behavior help your self
https://blogs.msdn.microsoft.com/saponsqlserver/2015/10/23/sql-server-alwayson-summary/
Cheers,
Shashank
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