Understanding the Windows Server Failover Cluster Quorum in Windows Server 2012 R2

 Editor’s note: In partnership with Microsoft Press, now celebrating their 30th year, MVPs have been contributing to an ongoing guest series on their official team blog. Today’s article is from Cluster MVP David Bermingham which is the 40th in the series.


Understanding the Windows Server Failover Cluster Quorum in Windows Server 2012 R2

Before we get started with all the great new cluster quorum features in Windows Server 2012 R2, we should take a moment and understand what the quorum does and how we got to where we are today.  Rob Hindman describes quorum best in his blog post

“The quorum configuration in a failover cluster determines the number of failures that the cluster can sustain while still remaining online.”

Prior to Windows Server 2003, there was only one quorum type, Disk Only. This quorum type is still available today, but is not recommended as the quorum disk is a single point of failure. In Windows Server 2003 Microsoft introduce the Majority Node Set (MNS) quorum. This was an improvement as it eliminated the disk only quorum as a single point of failure in the cluster. However, it did have its limitations. As implied in its name, Majority Node Set must have a majority of nodes to form a quorum and stay online, so this quorum model is not ideal for a two node cluster where the failure of one node would only leave one node remaining. One out of two is not a majority, so the remaining node would go offline.  Continue reading full article here

 About the author

Dave Bermingham is recognized within the technology community as a high
availability expert and has been honored by his peers by being awarded as a Microsoft MVP in Clustering since 2010.

Dave's work as director of Technical Evangelist at SIOS has him focused on evangelizing Microsoft
high availability and disaster recovery solutions as well as providing
hands on support, training and professional services for cluster
implementations. Dave hold numerous technical certifications and draws
from over twenty years of experience IT, including work in the finance,
healthcare and education fields, to help organizations design solutions to
meet their high availability and disaster recovery needs.  Read David’s blog or follow him on Twitter.  

 About MVP Monday

The MVP Monday Series is created by Melissa Travers. In this series we work to provide readers with a guest post from an MVP every Monday. Melissa is a Community Program Manager, formerly known as MVP Lead, for Messaging and Collaboration (Exchange, Lync, Office 365 and SharePoint) and Microsoft Dynamics in the US. She began her career at Microsoft as an Exchange Support Engineer and has been working with the technical community in some capacity for almost a decade. In her spare time she enjoys going to the gym, shopping for handbags, watching period and fantasy dramas, and spending time with her children and miniature Dachshund. Melissa lives in North Carolina and works out of the Microsoft Charlotte office.


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