Log-Structured File System OOB Data Recovery
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Solution Overview
Problem
In log-structured file systems using an out-place update mechanism, file data cannot be accessed after a power-off if index addresses have not been established, and establishing index information in a short time leads to increased data writing and reduced performance.
Innovation Solution
A data access method and apparatus that writes file attribute information to out-of-band data during file updates, allowing for restoration of file access after power-off by using this information to establish index addresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the processing device establishes index information quickly after power-on to ensure file accessibility, then file access timeliness is improved, but a large amount of data must be written in a short time which reduces processing device performance
Solution Approach 1:
The patent applies preliminary action by writing file attribute information to OOB data during the file writing process itself, before power-off can occur. This advance preparation ensures that when power is restored, the index information can be quickly recovered from the OOB data without requiring intensive processing, thus resolving the contradiction between fast recovery and performance maintenance
Solution Approach 2:
The patent creates a copy of essential index information (file attribute information) and stores it in OOB data. This copying mechanism allows the system to recover index information quickly after power-off by reading from the OOB data copy rather than reconstructing it from scratch, improving access timeliness without overwhelming the processing device
2Reliability
If the processing device writes file attribute information to OOB data during every file update, then file accessibility after power-off is ensured, but the complexity of the writing process increases
Solution Approach 1:
The patent merges the file attribute information writing operation with the existing file writing process. By integrating these operations, the system ensures file accessibility after power-off without requiring a separate, complex writing process, thus resolving the contradiction between reliability improvement and process complexity
Data Source
AI summary
A data access method performed by a processing device is disclosed. The processing device manages a storage device based on a log-structured file system (LFS), where the processing device writes a target file to the storage device based on an out place update (OPU) mechanism; and the processing device writes file attribute information corresponding to the target file in the storage device to out of band (OOB) data of the storage device, to restore, after abnormal power-off, access to the target file by using the file attribute information stored in the OOB data. In this way, when writing the target file to the storage device, the processing device may write a file attribute corresponding to the target file to the OOB data, so that after abnormal power-off, access to the target file may be restored by using the file attribute information.