RAID Data Recovery Skipping Invalid Pages
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Solution Overview
Problem
In RAID systems, data recovery from a broken drive is time-consuming due to the need to read and write data from large capacity drives, even with solid-state drives, which takes substantial time despite improved read/write speeds.
Innovation Solution
A data recovery method that recognizes blank or invalid data pages, performs parity checks to recover data, and skips these pages, allowing for faster data recovery by focusing on valid data pages and utilizing log-based writing and stripping processing across multiple drives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data recovery is performed by reading and writing all data pages from large capacity drives, then complete data recovery is achieved, but data recovery time becomes substantial
Solution Approach 1:
The patent extracts and identifies blank data pages from the recovery process using a mapping table that tracks which pages contain valid data. By extracting only the necessary valid data pages for recovery operations while skipping blank pages, the system achieves complete data recovery without the time penalty of processing all pages.
Solution Approach 2:
The patent applies partial action by performing recovery operations only on valid data pages rather than all data pages. The mapping table enables the system to identify and process only the necessary portion of data pages, achieving sufficient recovery without excessive processing of blank or already-recovered pages.
2Speed
If solid-state drives are used to improve read/write speed, then data transfer speed increases, but data recovery time remains substantial due to large drive capacities
Solution Approach 1:
The patent applies partial action by processing only valid data pages identified through the mapping table. Even with high-speed SSDs, recovering only the necessary portion of data pages (而非 all pages) significantly reduces total recovery time while maintaining data integrity.
3Measurement precision
If parity check calculation is performed on all data pages, then data recovery accuracy is ensured, but processing time increases
Solution Approach 1:
The patent extracts only valid data pages using the mapping table before performing parity check calculations. This extraction step ensures that parity operations are applied only to pages that contain data requiring recovery, maintaining accuracy while reducing unnecessary computational overhead on blank pages.
Solution Approach 2:
The patent applies partial action by limiting parity check calculations to only those data pages identified as valid through the mapping table. This partial processing approach maintains recovery accuracy for necessary pages while avoiding excessive calculation on blank pages.
Data Source
AI summary
A data recovery method for a Redundant Array of Independent Disks (RAID) system is provided. The RAID system includes a plurality of drives and a processor. Each drive includes a plurality of data pages. The drives form a plurality of data strips over the drives through stripping processing. Each data strip includes one of the data pages of every drive. The processor writes data to the data strips in a log-based manner and records whether each data page of each data strip is valid or invalid. During recovery of data from a broken one of the drives, data is recovered from a corresponding valid or written data page but is not recovered from a corresponding invalid or blank data page.