how can you sure WFCS is the cause?

John JY 221 Reputation points
2021-09-21T16:16:55.337+00:00

Hi all,

we have SQL AG role set up on Windows 2012R2 up OS. When SQL AG failovered, how can you sure that
WFCS caused and not AG role?

Thank you!

SQL Server
SQL Server
A family of Microsoft relational database management and analysis systems for e-commerce, line-of-business, and data warehousing solutions.
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Windows Server Clustering
Windows Server Clustering
Windows Server: A family of Microsoft server operating systems that support enterprise-level management, data storage, applications, and communications.Clustering: The grouping of multiple servers in a way that allows them to appear to be a single unit to client computers on a network. Clustering is a means of increasing network capacity, providing live backup in case one of the servers fails, and improving data security.
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  1. CathyJi-MSFT 21,061 Reputation points Microsoft Vendor
    2021-09-22T01:44:27.493+00:00

    Hi @John JY ,

    We need to start from SQL server error log and windows cluster log to analysis why SQL AG failover. The log will tell you that SQL or windows cause this issue.

    Generate and analyze the CLUSTER.LOG for an Always On availability group

    Use the cluster /log /g command at the command prompt. This command generates the cluster logs to the \windows\cluster\reports directory on each WSFC node. or use the Get-ClusterLog PowerShell cmdlet. Refer to MS document Generate and analyze the CLUSTER.LOG for an Always On availability group.


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  2. Limitless Technology 39,296 Reputation points
    2021-09-22T09:47:20.97+00:00

    Hello @John JY ,

    Windows Server Failover Cluster (WSFC) A WSFC is a group of independent servers that work together to increase the availability of applications and services.

    An Always On Failover Cluster Instance (FCI) is a SQL Server instance that is installed across nodes in a WFCS. This type of instance depends on resources for storage and virtual network name.

    High availability for an Always On solution is accomplished through proactive health monitoring of physical and logical WFCS cluster resources, together with automatic failover onto and re-configuration of redundant hardware. A system administrator can also initiate a manual failover of an availability group or SQL Server instance from one node to another.

    https://learn.microsoft.com/en-us/sql/sql-server/failover-clusters/windows/windows-server-failover-clustering-wsfc-with-sql-server?view=sql-server-ver15

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    Hope this answers all your queries, if not please do repost back.
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  3. John JY 221 Reputation points
    2021-10-18T22:16:05.9+00:00

    @CathyJi-MSFT Thank you! sorry to reply you late. checked Windows failover operational logs and AG failed over first. Can we say AG is the cause? also, see heartbeat lost. Thank you for the help!