Online Consistent System Checkpoint for Storage Recovery
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Solution Overview
Problem
Conventional storage systems face challenges in recovering from failures due to data/metadata inconsistency, requiring prolonged downtime and expertise, with no guarantee of successful recovery if configuration has changed or metadata failed to persist.
Innovation Solution
The implementation of an online system checkpoint that maintains a consistent point-in-time image of volume configuration, logical volume space, metadata, and physical data storage, allowing for transparent recovery without impacting normal host operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional storage systems use metadata journals to preserve consistency, then system consistency can be recovered after failure, but recovery requires prolonged downtime and expertise, and there is no guarantee of successful recovery if the journal fails to persist
Solution Approach 1:
The system performs preliminary actions by continuously maintaining a consistent point-in-time image of the entire storage system (volumes, metadata, and physical data) before failures occur. This checkpoint is updated periodically or based on events, ensuring that a valid recovery state is always available without requiring prolonged recovery operations.
Solution Approach 2:
The invention creates a copy of the entire storage system state (not just metadata) at a consistent point in time. This checkpoint copy includes volume configuration, logical volume space, metadata layers, and physical data storage, allowing the system to restore from this complete copy rather than attempting to replay metadata journals.
2Ease of repair
If conventional storage systems use metadata journals for recovery, then system consistency can be restored, but the process requires expertise on disk data/metadata layout and content
Solution Approach 1:
The system performs self-service recovery by automatically restoring from the consistent checkpoint image without requiring manual intervention or expertise. The recovery process is automated and can be initiated by simply bringing the system online, eliminating the need for administrators to understand complex metadata layouts or perform manual reconstruction operations.
3Productivity
If the system maintains a consistent point-in-time image for recovery, then recovery can be performed online without impacting normal host operations, but additional storage resources are required to maintain the checkpoint
Solution Approach 1:
The consistent checkpoint image serves multiple functions: it acts as a recovery mechanism for failed systems, provides a point-in-time snapshot for potential rollback scenarios, and maintains data consistency across all layers. This multi-functionality justifies the allocation of storage resources for maintaining the checkpoint.
Data Source
AI summary
Described embodiments provide systems and methods for operating a storage system wherein an online consistent system checkpoint is generated. The checkpoint contains a point in time image of a system and is used for providing recovery of the system to a known good state. In one embodiment the checkpoint includes volume configuration data, logical volume space, a plurality of layers of metadata, and physical data storage.