Cluster database

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Cluster database

The cluster registry is stored in the cluster database on each node. By default, the cluster database for a single quorum device server cluster is located at %systemroot%\Cluster\CLUSDB; for a majority node set server cluster, the cluster database is located at %systemroot%\Cluster\MNS.%ResourceGUID%$\%ResourceGUID%$\MSCS. A copy of the cluster registry is also stored in the CHKxxx.TMP file on the quorum disk. The quorum log maintains consistency between the two versions of the cluster registry. The cluster database resides in the Windows ServerĀ 2003 family registry on each cluster node. It contains information about all physical and logical elements in a cluster, including cluster objects, their properties, and configuration data.


  • Do not use the net use command to connect to the share containing the cluster database files (%systemroot%\Cluster\MNS.%ResourceGUID%$\%ResourceGUID%$\MSCS) in a majority node set server cluster. Otherwise, the Majority Node Set resource (the quorum resource) may be unable to connect to the share and may fail to come online.

Each node's Cluster service maintains a consistent, updated image of the cluster database through the following mechanisms:

  • Global updates. The Cluster service replicates changes to the cluster database uniformly across all nodes.

    Changes to the cluster database are replicated across all nodes automatically every 4 hours and also when any of the following events occur:

    1. A resource is taken online.

    2. A resource is taken offline.

    3. The Resource Monitor detects a change to one of the registry keys.

  • Periodic checkpointing. The Cluster service on the node that owns the quorum resource regularly saves a copy of the cluster database to ensure consistency.

  • Quorum resource. The Cluster service ensures that the quorum resource's recovery log contains the most recent cluster database information. Any changes between checkpoints are logged to the quorum disk if the Cluster service fails to replicate it among all nodes. The main purpose of the quorum resource is to maintain cluster consistency.

For more information on the concepts in this topic, see: