Parallel Journal Replay for Metadata Restoration in Storage Controllers
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Solution Overview
Problem
Flash memory devices face reliability issues due to the loss of metadata, which is crucial for data integrity, and existing solutions are inefficient in restoring metadata after power failures or errors, leading to prolonged recovery times.
Innovation Solution
A storage device with a nonvolatile memory and a storage controller that generates and replays journal data in parallel to restore metadata, splitting journal data into groups based on dependency to facilitate faster and reliable recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If journal data is replayed sequentially to restore metadata, then reliability of metadata restoration is improved, but the time required for restoration increases
Solution Approach 1:
The patent divides journal data into multiple groups based on dependency relationships. Independent groups can be replayed in parallel while dependent groups maintain sequential processing within themselves. This segmentation allows simultaneous execution of multiple replay operations, reducing total restoration time while maintaining reliability through preserved dependency constraints.
Solution Approach 2:
The patent implements a dynamic replay strategy where the processing mode (parallel or sequential) is determined by the dependency characteristics of journal data groups. The system adaptively selects the optimal replay approach based on the specific metadata restoration scenario, balancing reliability requirements with time efficiency.
2Productivity
If parallel replay of journal data is implemented, then restoration speed is improved, but complexity of the replay system increases
Solution Approach 1:
By segmenting journal data into independent groups, the system enables parallel replay operations without requiring complex coordination mechanisms. Each group can be processed independently by separate replay units, simplifying the overall system architecture while achieving high restoration speed.
Solution Approach 2:
The patent performs preliminary classification of journal data into groups based on dependency relationships before the replay process begins. This pre-processing step organizes the data structure in advance, allowing parallel replay to proceed without complex real-time decision-making or coordination, thereby reducing system complexity.
3Ease of operation
If journal data is not grouped by dependency, then system operation is simpler, but metadata restoration reliability decreases
Solution Approach 1:
The patent segments journal data into dependency-based groups, where each group contains journal entries that must be processed together to maintain metadata consistency. This segmentation ensures that dependent operations are executed as atomic units, preventing partial or inconsistent restoration while keeping the overall process manageable through clear group boundaries.
Data Source
AI summary
Disclosed is a storage device which includes a nonvolatile memory device, and a storage controller that controls the nonvolatile memory device and updates metadata based on an operation of the nonvolatile memory device, and the storage controller includes a journal data generator that generates a plurality of journal data associated with the update of the metadata, and a journal data replayer that replays the plurality of journal data in parallel to restore the metadata.