Understanding Dynamic Quorum in a Microsoft Failover Cluster

Windows Server 2012: Failover Clustering Deep Dive

Microsoft introduced an advanced quorum configuration option in Windows Server 2012/R2. You can choose to enable dynamic quorum management by cluster. There are major benefits of having dynamic quorum in any Microsoft cluster whether for Exchange DAG, SQL cluster, Hyper-v cluster or file server cluster. When you configure dynamic quorum, the cluster dynamically manages the vote assignment to nodes, based on the state of each node. Votes are automatically removed from nodes that leave active cluster membership, and a vote is automatically assigned when a node re-joins the cluster. Dynamic quorum remove dependencies of a quorum disk in Hyper-v and also enable multi-site cluster in a diverse geographic location without sharing common disk.


  • 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.
  • The cluster software automatically configures the quorum for a new cluster, based on the number of nodes configured and the availability of shared storage.


  • 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.
  • If you have explicitly removed the vote of a node, the cluster cannot dynamically add or remove that vote.

How to configure a dynamic quorum?

Configure a standard cluster as you do in a Microsoft environment. Then use Quorum Configuration Wizard in Cluster Manager to configure advanced quorum.

  1. In Failover Cluster Manager, select the cluster that you want to change.
  2. With the cluster selected>under Actions>click More Actions> and then click Configure Cluster Quorum Settings> Click Next.
  3. On the Select Quorum Configuration Option page>click Advanced quorum configuration and witness selection
  4. On the Select Voting Configuration page>select an option to assign votes to nodes. By default, all nodes are assigned a vote.
  5. On the Configure Quorum Management page> enable the Allow cluster to dynamically manage the assignment of node votes
  6. On the Select Quorum Witness page>select Do not configure a quorum witness, and then complete the wizard
  7. Click Next>then click Next.

Once quorum is reconfigured then you run the Validate Quorum Configuration test to verify the updated quorum settings. Follow the steps to validate quorum.

  1. In Failover Cluster Manager, select the cluster> run the Validate Quorum Configuration test to verify the updated quorum settings.

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