HDD Spin-Up Controller Threshold Logic for Storage Systems
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Solution Overview
Problem
In storage systems with multiple hard disk drives (HDDs), when a large number of HDDs are spun down due to power supply issues, the processing load on the control device increases, leading to longer restoration times and stagnant access processing for other HDDs.
Innovation Solution
A storage system with a magnetic disk apparatus and a control apparatus that includes a spin-up controller to restore spun-down HDDs, and a separate controller that temporarily prevents system use when a predetermined threshold of HDDs are spun down, allowing the HDDs to be spun up after a set period without increasing the control device's processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control device restores multiple spun-down HDDs simultaneously, then the system availability is improved, but the processing load on the control device increases and access processing for other HDDs becomes stagnant
Solution Approach 1:
The patent segments the HDD restoration process by introducing a threshold mechanism that divides the restoration operations into batches. When the number of spun-down HDDs reaches a predetermined threshold, the control device suspends further restoration operations and waits for a predetermined time period, thereby segmenting the continuous restoration process into manageable intervals that prevent excessive processing load accumulation.
Solution Approach 2:
The patent implements preliminary action by having the control device count the number of spun-down HDDs before initiating restoration operations. This preliminary counting and threshold checking prevents the control device from immediately attempting to restore all spun-down HDDs simultaneously, thereby preparing the system in advance to handle restoration operations in a controlled manner that avoids overwhelming processing load.
2Speed
If the control device continuously monitors and restores spun-down HDDs, then the system responsiveness is improved, but the time necessary for restoring each HDD becomes longer
Solution Approach 1:
The patent implements periodic action by introducing a predetermined time period that elapses between restoration operations. The control device suspends restoration operations for a predetermined time after reaching the threshold, creating periodic intervals that allow the system to recover and prevent continuous uninterrupted restoration attempts, thereby reducing the time necessary for each individual HDD restoration while maintaining overall system responsiveness.
3Ease of operation
If the control device permits access to all HDDs including spun-down ones, then the ease of operation is improved, but the system stability deteriorates due to increased processing load
Solution Approach 1:
The patent introduces an intermediary mechanism in the form of a threshold-based control logic that mediates between the desire for easy access to all HDDs and the need for system stability. The control device uses this intermediary threshold checking mechanism to determine when to permit restoration operations, thereby controlling access to spun-down HDDs in a way that maintains system stability while preserving ease of operation under normal conditions.
Data Source
AI summary
In a storage system, when power supply to HDDs is instantaneously interrupted, a spin up controller of a magnetic disk apparatus spins up the HDDs. On the other hand, based on a response for an access to the HDDs in the magnetic disk apparatus, when detecting that the HDDs as an access destination are spun down, a spin up controller of a control apparatus spins up the HDDs. When a certain number of the HDDs or more are spun down, a separate controller does not permit the magnetic disk apparatus to be used for a given length of time. While the magnetic disk apparatus is not permitted to be used, the HDDs are spun up by using the spin up controller of the magnetic disk apparatus.