The Cluster Service is a Microsoft® Windows NT® service used to control cluster activities. The Cluster Service performs such tasks as coordinating event notification, facilitating communication between other software components, handling failover operations, and managing configuration.
The Cluster Service is made up of several closely-related pieces called managers. The following table describes the function of each Cluster Service manager:
| Manager | Description |
|---|---|
| Checkpoint Manager | Responsible for saving data from the cluster database or from other portions of the system registry to files maintained on the quorum resource. |
| Database Manager | Controls access to the cluster database. |
| Event Log Manager | Replicates the Windows NT event log records across the nodes of a cluster. The Windows NT Event Viewer attached to any one of the nodes can be used to view cluster events. |
| Failover Manager | Handles the transferring of groups of resources from one node to another in response to a request from the Resource Manager. Works with the Resource Manager to manage resource dependencies and start and stop resources. |
| Global Update Manager | Provides update services to the cluster nodes, enabling the Database Manager to ensure that related changes to the cluster database take place consistently across the cluster. All changes to the cluster configuration and to its state are applied using the Global Update Manager. |
| Log Manager | Writes changes to the recovery log stored on the quorum resource when any of the cluster nodes are down. Takes checkpoints at appropriate moments, thereby helping to ensure that the local cluster databases are kept consistent across the cluster. Handles a partition in time, a situation that occurs when cluster nodes are not online at the same time. |
| Membership Manager | Works with the Node Manager and the Cluster Network Driver to maintain cluster membership and to provide membership information to other components in the Cluster Service. Keeps track of the nodes that are currently active members of the cluster and nodes that are configured as members but not active. |
| Node Manager | Maintains all node and network configuration and state information. Controls operation of the Cluster Network Driver. |
| Resource Manager | Initiates the transfer of cluster groups to alternate nodes by sending a failover request to the Failover Manager. Determines how ownership of the groups should be redistributed. |