Virtual Hard Disk RAID Capacity Expansion
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Solution Overview
Problem
Existing capacity expansion methods for distributed RAID systems require adding multiple hard disks at once to reduce reconstruction time, but this leads to long expansion times due to the need to migrate large amounts of small block data, and original RAID groups cannot be easily extended or reconstructed quickly.
Innovation Solution
Divide each hard disk into virtual hard disks of equal size, select and form virtual hard disk groups, and insert new hard disks to distribute data efficiently, using a distributed RAID algorithm to construct new RAID groups and migrate data within virtual hard disk groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If multiple hard disks are added at once to construct a new distributed RAID system, then the reconstruction time is reduced and hot spots are dispersed, but the capacity expansion time becomes long due to migrating large amounts of small block data
Solution Approach 1:
The patent divides each physical hard disk into multiple virtual hard disks, and further segments the data into small blocks that can be independently migrated. This segmentation allows the capacity expansion to proceed by migrating only the necessary small block data rather than moving entire large disks, significantly reducing the expansion time while maintaining the benefits of distributed RAID reconstruction.
2Adaptability or versatility
If original RAID groups are horizontally extended to added RAID groups, then the capacity expansion is achieved, but the reconstruction time of the original RAID group cannot be reduced
Solution Approach 1:
The patent introduces a dynamic virtual hard disk group structure that allows flexible reconfiguration. The virtual hard disk groups can dynamically adjust their composition and mapping relationships, enabling the system to extend capacity while simultaneously optimizing the reconstruction process of original RAID groups through flexible data remapping and redistribution.
3Device complexity
If added hard disks are added to the original RAID group respectively, then the capacity expansion is achieved with fewer hard disks added at once, but large amounts of small block data need to be migrated requiring long expansion time
Solution Approach 1:
The patent introduces virtual hard disks as intermediary entities between physical hard disks and RAID groups. These virtual hard disks serve as mediators that can be efficiently allocated and migrated, allowing the system to add capacity with fewer physical hard disks while reducing the data migration overhead by operating at the virtual disk level rather than moving individual small blocks across multiple disks.
Data Source
AI summary
Embodiments of the present invention provide a capacity expansion method and device, so as to reduce the time needed by capacity expansion of a hard disk. The method specifically includes: dividing, in a distributed redundant array of independent disks RAID system, each hard disk into virtual hard disks of equal size equally; dividing an original hard disk into X groups equally; selecting m virtual hard disks from each hard disk in sequence to form one original hard disk; selecting m virtual hard disks from each added hard disk and inserting the m virtual hard disks into the virtual hard disk group; moving, in the virtual hard disk group, data in virtual hard disks of the original hard disk to the virtual hard disks of the added hard disk. The present invention is applied to capacity expansion of a hard disk.