Memory Controller Dynamic Priority for Disk Rebuild Efficiency
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Solution Overview
Problem
Conventional disk array systems face inefficiencies in prioritizing and executing background processing, which can interfere with main processing, especially during rebuild operations in RAID systems, leading to potential data security issues and prolonged processing times.
Innovation Solution
A memory control apparatus that optimizes background processing by using a combination of 'optimum value' and 'fastest value' units of processing, with a wait time and count mechanism to minimize interference with main processing, ensuring efficient completion of background tasks without degrading main processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If background processing is executed on a high priority basis to complete it quickly, then the processing time for background tasks is reduced, but the processing efficiency of main processing deteriorates
Solution Approach 1:
The patent implements dynamic priority adjustment where the storage device automatically switches between executing background processing at high priority (when no main processing is pending) and main processing at high priority (when main processing requests are queued). This dynamic switching resolves the contradiction by adapting the priority scheme to real-time system state, ensuring background processing completes quickly when possible without permanently degrading main processing efficiency.
Solution Approach 2:
The system changes the parameter of processing priority dynamically based on the state of the processing queue. When the number of pending main processing requests exceeds a threshold, the priority parameter for background processing is reduced; otherwise, background processing maintains high priority. This parameter change strategy allows the system to achieve fast background processing completion while protecting main processing efficiency under load.
2Productivity
If background processing is executed on a low priority basis to maintain main processing efficiency, then the processing efficiency of main processing is maintained, but the processing time for background tasks increases
Solution Approach 1:
Instead of statically assigning low priority to background processing, the system dynamically adjusts priority based on real-time conditions. When the main processing queue is not full, background processing executes at high priority, significantly reducing its completion time without impacting main processing efficiency. This dynamic approach resolves the contradiction by making priority assignment conditional rather than fixed.
3Ease of operation
If a priority table is generated and registered on the storage device to control processing priority, then the processing priority can be determined, but complicated operations are required
Solution Approach 1:
The storage device is designed to autonomously determine processing priorities without requiring external priority tables or complex registration operations. The device self-monitors its own state (number of pending main processing requests) and automatically adjusts the priority of background processing accordingly. This self-service mechanism eliminates the need for complicated priority table generation and registration operations while maintaining effective priority control.
Solution Approach 2:
The patent extracts the priority control logic from the host system and embeds it directly in the storage device firmware. This extraction eliminates the need for complex host-side priority table management and simplifies the overall system operation. The storage device independently handles priority determination based on its internal state, removing the burden of complicated control operations from the host system.
Data Source
AI summary
A method completes background processing within a shortest possible time without degrading an efficiency of main processing executed in a system. The system includes a control apparatus including a plurality of hard disks and a memory controller configured to control an access to the hard disk. The memory controller changes a unit of the background processing, which is changed according to a state of a plurality of storage devices. In changing the unit of processing, the memory controller monitors the presence or absence of an access for the main processing coming from a main controller, and changes the unit of the background processing to a first unit of processing or to a second unit of processing, which is smaller than the first unit of processing according to a result of the monitoring.