RAID-6 Auto-Correction via Sequential Drive Mapping
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Solution Overview
Problem
RAID-6 systems cannot correct data unless each disk drive in error is identified, leading to inability to provide corrected data when multiple disk drives fail, resulting in read errors.
Innovation Solution
A method that uses a dual parity generation engine to transfer data between cache and stage buffer memory, sequentially maps out disk drives to identify the faulty drive, and utilizes remaining drives to reconstruct and provide valid data to the processor, enabling auto-correction of errors in real time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RAID-6 system uses dual parity generation engine to detect failures in up to two disk drives, then fault tolerance is improved, but the system cannot correct data unless each disk drive in error is identified
Solution Approach 1:
The patent segments the disk drive array into individual addressable units, allowing the system to systematically map out and test each disk drive independently. By dividing the array into separable components, the system can identify which specific drive is causing errors without having to replace or reconfigure entire RAID groups.
Solution Approach 2:
The patent implements preliminary error identification through systematic mapping of disk drives before attempting data correction. The controller proactively tests and identifies faulty drives by mapping them out individually, so that when errors occur, the correction process can proceed immediately without needing to first identify the problematic drive.
2Measurement precision
If the system maps out disk drives sequentially to identify the faulty drive, then error identification is achieved, but data transfer time is increased
Solution Approach 1:
The patent performs preliminary mapping and identification of faulty disk drives during normal operations or maintenance windows. By proactively identifying and mapping out problematic drives before they cause read errors, the system eliminates the need for time-consuming sequential testing during actual data retrieval operations.
Solution Approach 2:
The system implements self-service error identification through automatic mapping and testing of disk drives. The RAID controller autonomously identifies faulty drives by systematically mapping them out and testing data integrity, without requiring manual intervention or time-consuming sequential testing when errors occur.
3Reliability
If the system reports a read error to the processor when disk drive failures occur, then error detection is achieved, but productivity is reduced due to re-reading from disk storage devices
Solution Approach 1:
The patent extracts faulty disk drives from the active array by mapping them out, separating problematic components from the functional system. This allows the remaining healthy drives to continue operating without interference from the faulty drive, enabling error correction without requiring the processor to initiate time-consuming re-read operations.
Solution Approach 2:
The patent introduces an intermediary mapping mechanism between the processor and the disk drives. The RAID controller acts as an intermediary that intercepts read errors, identifies the faulty drive through systematic mapping, and retrieves data from redundant copies before presenting corrected data to the processor, thereby preventing productivity loss from re-read operations.
4Measurement precision
If the system uses sequential mapping to identify the faulty disk drive, then the correct drive is identified, but device complexity is increased
Solution Approach 1:
The patent implements a universal mapping mechanism that serves multiple functions: it identifies faulty drives, tests data integrity, and enables error correction all through a single systematic process. The same mapping infrastructure used for normal array management is leveraged for error identification, eliminating the need for separate complex testing procedures.
Solution Approach 2:
The system performs self-service fault identification using the existing RAID controller and array structure. The controller autonomously executes mapping and testing sequences to identify faulty drives without requiring external testing equipment or complex additional hardware, utilizing already-present components to accomplish error identification.
Data Source
AI summary
A method for auto-correction of errors in an array of disk storage devices having a plurality of disk storage devices dedicated to storing parity data to provide fault tolerance for a loss of at least two of the plurality of disk storage devices. A read operation from the storage channels transfers data to a plurality of disk channel memories. The data in the disk channel memories is checked to confirm the data is valid. Responsive to detection of invalid data, the data may be tested to identify the disk storage channel in error, including sequentially excluding data read from a different one of the plurality of disk channel memories from a parity check and determining the validity of data from remaining disk channel memories. If valid data is obtained, the disk storage channel from which the data was excluded is identified as the disk storage channel in error.