Disk Array Wear Balancing via Dynamic Data Migration
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Solution Overview
Problem
In disk arrays, data processing often concentrates on certain disks, leading to uneven wear and increased failure rates, which results in high reconstruction costs and reduced reliability and availability, as existing wear leveling methods only address within-disk balancing and not between-disks.
Innovation Solution
A method that determines the degree of wear and accumulative block writes for each disk, migrating data from disks with higher wear and write heat to those with lower wear and write heat to achieve balanced usage and extend the service life of disks in the array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data is stored on a disk array with multiple mapped disk arrays sharing one physical disk array, then the utilization efficiency of the disk is greatly improved, but data may overly concentrate on some disks making them prone to failure
Solution Approach 1:
The patent implements dynamic data migration between disk extents based on real-time wear levels and write heat metrics. The system continuously monitors disk health and automatically relocates data from high-wear extents to low-wear extents, making the storage system adaptive to changing disk conditions rather than static.
Solution Approach 2:
The system employs feedback mechanisms by monitoring write heat and wear levels of disk extents, then using this information to guide data migration decisions. The controller receives feedback about disk health status and adjusts data placement accordingly, creating a closed-loop control system that prevents disk failure.
2Duration of action of stationary object
If data migrates frequently to balance wear across disks, then the service life of disks is extended, but the complexity of data management increases
Solution Approach 1:
The patent segments the disk into multiple smaller units called disk extents, allowing granular-level wear leveling and data migration. Instead of managing entire disks, the system operates at the extent level, which reduces the complexity of tracking and migrating data while achieving better wear distribution.
Solution Approach 2:
The system introduces disk extent as an intermediary layer between the logical disk and physical storage. This intermediary abstraction simplifies management by providing a uniform interface for data placement and migration, hiding the complexity of underlying disk variations from the data management logic.
3Device complexity
If wear leveling is performed only within a single disk, then the implementation is simple, but the overall reliability of the disk array is reduced due to between-disk wear imbalance
Solution Approach 1:
The patent creates a universal wear leveling mechanism that operates across multiple disks simultaneously. The disk extent management system provides multi-functionality by handling both within-disk and between-disk wear balancing through a unified approach, eliminating the need for separate wear leveling strategies.
Solution Approach 2:
The system merges the wear leveling operations across multiple disks into a unified process. By combining data from multiple disks and redistributing it across available extents regardless of disk boundaries, the system achieves comprehensive wear balancing while maintaining implementation simplicity through a single integrated mechanism.
Data Source
AI summary
Embodiments of the present disclosure relate to a method, device and computer program product for managing a disk array. The method comprises determining respective degrees of wear for a plurality of disks in the disk array, each of the plurality of disks comprising a plurality of disk extents, and each disk extent comprising a plurality of blocks. The method further comprises determining respective numbers of blocks that are accumulatively written into the plurality of disks during a predetermined period of time. The method further comprises migrating data among the plurality of disks based on the degrees of wear and the number of the accumulatively written blocks.