Storage System Rebuild Coupling Degree Analysis
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Solution Overview
Problem
Existing storage systems face challenges in efficiently rebuilding data after a storage device failure, particularly in balancing load and minimizing access conflicts during parallel rebuild operations, which can lead to reduced response speed and inefficiency.
Innovation Solution
A method and apparatus that determine the coupling degree between stripes to select storage devices for rebuilding, minimizing conflicts and optimizing parallel rebuild efficiency by identifying candidate storage devices based on the coupling degree, ensuring lower conflict during rebuild operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple stripes are rebuilt in parallel to improve rebuild efficiency, then productivity is improved, but access conflicts between storage devices increase leading to reduced response speed
Solution Approach 1:
The patent calculates coupling degrees between all stripes before the rebuild operation begins, and pre-determines the rebuild sequence based on these coupling degrees. This preliminary planning allows the system to execute parallel rebuilds optimally without real-time conflicts, as the schedule is already optimized to minimize access conflicts while maximizing parallelism.
Solution Approach 2:
The patent dynamically adjusts the parallel rebuild strategy by calculating coupling degrees and determining which stripes can be rebuilt in parallel versus which must be sequential. The system flexibly manages the rebuild process by adapting the parallelization level based on the calculated coupling relationships, rather than using a fixed parallel or sequential approach.
2Device complexity
If storage devices are selected randomly for rebuild operations, then device complexity is reduced, but access conflicts increase reducing rebuild efficiency
Solution Approach 1:
The patent introduces a feedback mechanism where the coupling degree calculation provides information about the relationship between stripes, which then feeds into the storage device selection process. This feedback allows the system to make informed decisions about which storage devices to use for parallel rebuilds, optimizing the selection based on the calculated coupling relationships rather than random selection.
Solution Approach 2:
The patent changes the selection parameter from random selection to coupling-degree-based selection. By using the coupling degree as the selection criterion, the system transforms the device selection process into an optimized process that considers the relationships between stripes, thereby reducing access conflicts and improving rebuild efficiency.
Data Source
AI summary
Techniques for managing a storage system involve: in response to a storage device in a group of storage devices failing, determining multiple stripes in the storage system which are associated with the failed storage device; selecting a first storage device and a second storage device from the group of storage devices respectively, the first storage device and the second storage device being a first candidate and a second candidate of storage devices for rebuilding a first stripe and a second stripe among the multiple stripes to form a first rebuilt stripe and a second rebuilt stripe respectively; obtaining a coupling degree between the first rebuilt stripe and the second rebuilt stripe, the coupling degree describing a conflict degree of rebuilding the first stripe and the second stripe in parallel; and identifying the first candidate and the second candidate on the basis of the obtained coupling degree.