Layered Cluster Fencing Coordinator for Data Availability

The patent introduces a fencing coordinator as an intermediary component that mediates between the application layer fencing logic and operating system layer fencing logic. The coordinator receives fencing requests from both layers, coordinates their execution to prevent conflicts, and ensures that fencing actions are performed in a controlled sequence. This intermediary structure allows independent failover logic to operate at both layers while preventing the harmful effect of conflicting fencing actions that would cause data unavailability.

The patent merges the fencing coordination functionality into a centralized component that handles both application layer and operating system layer fencing requests. Instead of having separate coordination mechanisms for each layer, the patent combines them into a unified fencing coordinator that manages redundant capabilities across multiple computers. This merging approach maintains application continuity through redundancy while reducing overall system complexity by consolidating coordination logic.

The patent implements preliminary action by having the fencing coordinator evaluate and prepare fencing requests before actual fencing actions are executed. When fencing requests arrive from both application and operating system layers, the coordinator预先 (in advance) assesses their compatibility, determines the correct execution sequence, and prevents conflicting actions. This preliminary coordination maintains fast failover responsiveness while ensuring service continuity by avoiding conflicting fencing actions.