Storage Controller Check-Code Comparison for RAID Failure Recovery
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Solution Overview
Problem
Current storage systems fail to detect and restore data failures effectively, particularly in RAID configurations, due to limitations in verifying data integrity and addressing write-error and read-error failures.
Innovation Solution
A storage controller and method that uses check data and update sequence information to verify data integrity by comparing first and second check data stored in different storage areas, allowing for detection and restoration of data failures, even in cases where RAID restoration is not possible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If guarantee code is added to data and stored in storage device, then data integrity verification is improved, but write-error failure cannot be detected
Solution Approach 1:
The guarantee code is divided into two separate codes: first guarantee code stored with data, and second guarantee code stored separately. This segmentation allows the second guarantee code to serve as an independent verification mechanism that can detect write errors by comparing against the first guarantee code, thereby resolving the limitation where traditional single guarantee codes cannot detect write errors.
Solution Approach 2:
The second guarantee code acts as an intermediary verification mechanism. When data is read back, the system recalculates the guarantee code from the retrieved data and compares it with the stored second guarantee code. This intermediary comparison process enables detection of write errors that would otherwise go undetected, while maintaining the original data integrity verification function.
2Measurement precision
If historical information is added to data in first sector and second sector, then data verification is improved, but restoration of detected errors is not considered
Solution Approach 1:
The system performs preliminary error detection using the two guarantee codes before restoration is needed. When a mismatch is detected between first and second guarantee codes, the system immediately identifies the error location and type. This preliminary detection enables subsequent restoration actions to be taken, addressing the gap in prior art where verification occurred but restoration was not considered.
Solution Approach 2:
The comparison between first and second guarantee codes provides feedback about data integrity status. When errors are detected, this feedback triggers restoration procedures using RAID mechanisms or other recovery methods. The feedback loop closes the gap between detection and restoration, ensuring that verified errors are actively addressed rather than merely identified.
Data Source
AI summary
Even when a failure incapable of being detected by a single guarantee code occurs in data, a storage controller of the present invention can detect and restore this failure. The controller, upon receiving a write command from a host, establish a first data guarantee code in the write data, and establish a second data guarantee code in the parity related to the write data. Upon receiving a read command from the host, the controller determines the correctness of the data based on the first data guarantee code, and also detects the presence or absence of a failure by comparing the first data guarantee code with the second data guarantee code. When a failure is detected, the controller restores the failure on the basis of RAID technology.