Which statement about a disk witness is correct?

• A. Disk witness stores a backup copy of the cluster configuration on disk.
• B. A disk witness provides a tie-break by storing cluster configuration data on disk to help quorum decisions.
• C. Disk witness is a type of network device.
• D. Disk witness automatically expands the cluster.

Answer: (B)

In failover clustering, quorum is about having a majority of votes to ensure the cluster is healthy and can make decisions. A disk witness contributes by providing an extra vote stored on disk, which helps break ties in quorum calculations when nodes lose connectivity or there are an even number of votes. This stored data on the disk witness supports decisions about whether the cluster still has quorum, preventing split-brain scenarios. It’s not a full backup of the cluster configuration, it’s not a network device, and it doesn’t cause the cluster to expand automatically. That makes the statement about providing a tie-break by storing cluster data on disk to help quorum decisions the best description.