I/O Error Interception for Application Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high availability server cluster environments, existing systems face challenges in efficiently handling input/output (I/O) errors, particularly in maintaining data consistency and reducing the time required for application recovery, as they often necessitate time-consuming recovery operations and reinitialization of applications.
Innovation Solution
A method and apparatus that intercept I/O errors, prevent application execution, complete I/O operations via an alternate path, create a checkpoint image of the application state, and transfer this image to another server for seamless resumption, thereby avoiding the need for extensive recovery operations and maintaining application availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional application restart procedures are used after I/O errors, then data consistency can be maintained, but recovery time increases significantly due to required reinitialization and recovery operations
Solution Approach 1:
The system performs preliminary actions by creating a checkpoint image of the application state before the I/O error occurs. This checkpoint captures the application's process state, allowing the application to resume execution from this saved state rather than restarting from initialization, thereby reducing recovery time while maintaining data consistency through the checkpoint mechanism
Solution Approach 2:
The invention creates a copy of the application state in the form of a checkpoint image. This checkpoint image contains the process state and can be transferred to another server, enabling the application to continue execution without full reinitialization. The copying of state information allows for rapid recovery while preserving data consistency
2Reliability
If application restart is performed after I/O errors, then system functionality is restored, but complexity of recovery operations increases due to fsck, journal log replay, and reconfiguration
Solution Approach 1:
The invention extracts the essential application state information into a checkpoint image, separating this critical data from the complex recovery operations. By taking out the application state as a self-contained unit, the system avoids the complexity of performing fsck, journal log replay, and reconfiguration operations, thereby simplifying the recovery process while restoring system functionality
Solution Approach 2:
The checkpoint image serves as an intermediary that bridges the gap between the error state and the restored functionality. Instead of directly performing complex recovery operations, the system uses the checkpoint image as an intermediate representation of the application state, which can be transferred and resumed on another server, thereby reducing recovery complexity
3Reliability
If full application reinitialization is performed after I/O errors, then data store consistency is ensured, but application availability decreases due to extended downtime
Solution Approach 1:
The system performs the preliminary action of creating a checkpoint image before the I/O error causes data inconsistency. This pre-prepared state allows the application to resume quickly without full reinitialization, maintaining data store consistency while minimizing availability loss. The checkpoint acts as a safety point that enables rapid recovery
Solution Approach 2:
By creating a copy of the application state in the checkpoint image, the system enables rapid recovery without requiring full reinitialization. This copy can be transferred to another server and resumed immediately, maintaining application availability while ensuring data consistency through the checkpoint mechanism
Data Source
AI summary
Embodiments comprise a plurality of computing devices that dynamically intercept process application I/O errors. Various embodiments comprise two or more computing devices, such as two or more servers, each having access to a shared data storage system. An application may be executing on the first computing device and performing an I/O operation when an I/O error occurs. The first computing device may intercept the I/O error, rather than passing it back to the application, and prevent the error from affecting the application. The first computing device may complete the I/O operation, and any other pending I/O operations not written to disk, via an alternate path, perform a checkpoint operation to capture the state of the set of processes associated with the application, and transfer the checkpoint image to the second computing device. The second computing device may resume operation of the application from the checkpoint image.