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Ashwan1234 asked ·

Always on with WSFC three nodes

SQL Server : 2016 SP2 enterprise servers
Windows: 2012 R2

We have already configured 2 nodes WSFC with quorum files share alwasyson configuration. Now we need to add other node as a secondary.
Having three nodes in total no meaning to have "quorum files share". therefore what is the recommendation practise I should follow change and configuration need to be happen in relation to the quorum

Highly appreciate your expert advice.


thanks

sql-server-general
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Ashwan1234 avatar image
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Ashwan1234 answered ·

hi Criszhan thank you for the great information,. As you commented Dynamic Quorum okey to configure with 3 nodes, how this will work with 3 nodes ? or its a default configuration as nothing to do for us(feature)

Following note says even you have 3 nodes, better to keep it witness share . I am not sure why and what for? what benefit we will get it from there .

https://www.mssqltips.com/sqlservertip/4434/dynamic-quorum-for-windows-server-2012-r2-cluster-to-support-sql-server-alwayson/
"In Windows Server 2012 R2, the recommendation is to always configure a witness regardless of the number of nodes."

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Hi,

or its a default configuration as nothing to do for us(feature)

Yes. Is enabled by default and will dynamically manage the assignment of node votes. You can run the PowerShell command below to check the Dynamic Quorum property.

Get-Cluster | fl Name, DynamicQuorum

With dynamic quorum management, it is also possible for a cluster to run on the last surviving cluster node. By dynamically adjusting the quorum majority requirement, the cluster can sustain sequential node shutdowns to a single node. But the Dynamic quorum management does not allow the cluster to sustain a simultaneous failure of a majority of voting members. To continue running, the cluster must always have a quorum majority at the time of a node shutdown or failure.

More details please check the following document.
https://docs.microsoft.com/en-us/windows-server/failover-clustering/manage-cluster-quorum#dynamic-quorum-management

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Criszhan-msft avatar image
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Criszhan-msft answered ·

Hi,

As a general rule, when you configure quorum, the voting elements in the cluster should be odd numbers.

After the third node is added to the wsfc cluster, you can run the Configure Cluster Quorum Wizard in failover cluster manager to modify the cluster quorum configuration option to "Use default quorum configuration", so the file share witness is not used.

But you can still keep the file share witness for Dynamic Quorum, the feature is introduced in the WSFC built on Windows Server 2012, which is enabled by default.

Check the following posts for more details.
https://dba.stackexchange.com/questions/154471/quorum-for-3-nodes-alwayson-availability-group
https://dba.stackexchange.com/questions/227703/do-we-really-need-a-file-share-witness

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Hi,

Is there any update on this case?
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