RAID Stripe Compression Layout for Efficient Parity Storage
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Solution Overview
Problem
Conventional data storage systems face inefficiencies in storage capacity and complexity due to the low compressibility of parity information, especially when using RAID technologies, which can lead to increased latency and reduced data reduction ratios, particularly when compressing data before parity calculation or when parity strips are uncompressible.
Innovation Solution
The proposed solution involves organizing user data into RAID stripes before compression, calculating parity on compressed data strips, and padding smaller strips to match the size of the largest strip, allowing for efficient storage and reducing the overhead of parity updates, while leveraging Log-Structured Array (LSA) techniques to distribute compressible data evenly across storage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If parity information is calculated before compression, then data protection is provided, but storage efficiency decreases due to low compressibility of parity information
Solution Approach 1:
The patent applies preliminary compression to data strips before calculating parity information. By compressing the data first and then calculating parity on the compressed data, the system achieves better storage efficiency while maintaining data protection. This reverses the conventional order of operations to optimize the compression ratio of the overall system.
2Quantity of substance
If compression is performed before parity calculation, then storage efficiency improves, but complexity of parity updates increases
Solution Approach 1:
The patent segments the data into multiple compressible data strips, calculates parity on these segmented compressed strips, and stores them separately. This segmentation approach allows for efficient parity updates by enabling selective recalculation of only the affected parity strips when data changes, rather than requiring full parity recalculation.
3Reliability
If uncompressible parity strips are stored, then data integrity is maintained, but storage capacity is wasted
Solution Approach 1:
The patent changes the state of parity information from uncompressible to compressible by calculating parity on already-compressed data strips. This parameter change in the data format allows the parity information itself to achieve better compression ratios, thereby improving storage capacity utilization while maintaining data integrity through the preserved parity information.
Data Source
AI summary
A technique for operating a data storage system includes receiving uncompressed data. The uncompressed data is organized into data strips of a stripe. The data strips are compressed subsequent to the organizing. Parity information for the compressed data strips is calculated. Storage of the compressed data strips and the parity information for the stripe is initiated on respective storage devices of the data storage system.