Configure Windows Cluster Quorum Witness

Clusters with an even number of members are vulnerable to "Split Brain". The best solution for this is to create a disk or share quorum member.

Computer clusters require 3 or more voting member systems to be stable.

A 2-node can become unstable in certain circumstances without a third node or a disk or share quorum member. This separate disk or share acts as an independent node for quorum operations.  Each cluster member will update records on a disk or share quorum folder which allows other quorum members to know the availability and health of each of the other members.

On clusters with an even number of cluster members are vulnerable to a condition known as “Split Brain” where half of the members lose contact with the other half.  The best solution for this is to create a disk or share quorum member.

  • A quorum disk must have a partition of at least 512 MB
  • A share must have at least 5 MB space available

When the cluster quorum is created, a directory will be created and populated with data.

Create the quorum

To create the quorum, run the following cluster commands:

#Create the quorum configuration
Set-ClusterQuorum –Cluster <cluster name> -NodeMajority

Create a disk quorum witness

To create a disk quorum :

Set-ClusterQuorum -NodeAndDiskMajority "Cluster Disk 2"

Info

The disk name under the Failover Cluster Manager should likely be changed to a more descriptive name other than Cluster Disk x. This can be done easily inside the Failover Cluster Manager.

Create a network share quorum witness

Set-ClusterQuorum -NodeAndFileShareMajority "\fileserverfsw"

Info

This network share must be on a system other than the clustered system. A network share cannot reside on the same cluster as the file system is managed by the cluster and must be available when the cluster is down or booting.

Reference:  Configure and Manage the Quorum in a Windows Server 2012 Failover Cluster

2 thoughts on “Configure Windows Cluster Quorum Witness”

  1. Top Fathers

    Thanks for this information. I configured my windows and wrote my article. It really worked.

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