Adaptive Storage Reclamation for SSDs
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Solution Overview
Problem
Current storage systems face inefficiencies in reclaiming storage capacity, particularly in solid-state drives (SSDs) and thin-provisioned storage, as existing methods often require frequent and resource-intensive reclamation processes that impact performance and can lead to unnecessary wear on SSDs.
Innovation Solution
An intelligent and adaptive storage manager is implemented to selectively and optimally manage storage reclamation by determining the best times for reclamation based on system state and benefit, distinguishing between user and system data, and adjusting reclamation workflows to minimize impact on the system, such as performing reclamation only when necessary and during low usage periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If reclamation is performed after each operation or periodically to ensure storage space is freed, then storage capacity is reclaimed, but performance of the storage system is significantly impacted
Solution Approach 1:
The patent implements dynamic reclamation scheduling that adapts to system conditions. The storage manager monitors system state and adjusts reclamation timing and intensity based on current workload, available capacity, and performance requirements. This allows the system to perform reclamation when it has minimal impact on performance while still ensuring storage capacity is reclaimed when needed.
Solution Approach 2:
The system changes reclamation parameters (timing, frequency, intensity) based on system state. Instead of fixed periodic reclamation or reclamation after every operation, the storage manager dynamically adjusts reclamation parameters considering factors like available storage capacity, current performance load, and predicted future needs, thereby optimizing the balance between capacity reclamation and performance maintenance.
2Loss of time
If reclamation operations are scheduled to occur before shortage of erased blocks arises to avoid extended periods of reclaim, then reclamation time is distributed, but complex estimation of additional host data and reclaim operations is required
Solution Approach 1:
The storage manager implements feedback mechanisms that monitor system state and adjust reclamation scheduling accordingly. By continuously observing storage capacity usage, performance metrics, and reclamation effectiveness, the system learns from past behavior and refines its scheduling decisions. This feedback loop simplifies the scheduling complexity by using observed patterns rather than requiring complex predictive models.
Solution Approach 2:
The system performs preliminary reclamation actions before storage capacity becomes critically low. By proactively initiating reclamation operations when conditions are favorable (lower workload, sufficient capacity buffer), the system avoids the need for complex emergency reclamation scheduling while still preventing storage shortages and distributing reclamation time effectively.
3Quantity of substance
If reclamation is performed frequently to ensure storage space availability, then storage capacity is reclaimed, but unnecessary wear on SSD cells is caused
Solution Approach 1:
The system performs reclamation only to the extent necessary to maintain adequate storage capacity, rather than continuously or excessively. The storage manager monitors capacity thresholds and initiates reclamation only when needed, performing partial reclamation operations that free sufficient space without requiring complete reclamation of all used blocks. This reduces unnecessary write/erase cycles on SSD cells while maintaining adequate storage capacity.
4Productivity
If asynchronous reclamation is performed on thin-provisioned disks to reduce impact on performance, then performance impact is minimized, but storage space may not be freed promptly
Solution Approach 1:
The system implements periodic reclamation operations that occur at scheduled intervals during periods of lower system activity. Instead of immediate synchronous reclamation that would impact performance, or purely event-driven asynchronous reclamation that may delay storage freeing, the system uses periodic scheduling to balance both requirements - performing reclamation regularly enough to free storage space in a timely manner while scheduling during low-activity periods to minimize performance impact.
Data Source
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AI summary
In some examples, a system may include at least one class of storage that is configured for having freed storage space reclaimed to enable reuse of the freed storage space. For instance, the system may determine whether a volume corresponding to the at least one class of storage is used to store system data or user data. If the volume is used to store user data, then the system may determine whether any of the user data has been deleted from the volume. If data has been deleted from the volume, the system may determine whether an available capacity of the volume is less than a remaining capacity threshold before performing reclamation on the at least one storage device corresponding to the volume. Alternatively, if the volume is used to store system data, the system may perform reclamation based on an elapsed period of time since the last reclamation.