Storage Array Power Reduction via Disk Spin-Down and SSD Buffering
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Solution Overview
Problem
The rising energy costs and heat generation in operating electronic appliances, such as RAID storage systems, lead to increased operational expenses due to high power consumption and cooling requirements.
Innovation Solution
A method that involves writing data to a multiple disk array, synchronously copying it to a read spare drive, spinning down the array during idle periods, using solid state storage for additional writes, and synchronously copying data back to the disk array when needed, thereby reducing power consumption and cooling demands through a centralized cooling system and pulse-width modulation of fans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the multiple disk array remains spinning to handle write operations, then write speed is maintained, but power consumption increases
Solution Approach 1:
Data is pre-written to solid state storage before being transferred to the multiple disk array. This preliminary action allows the disk array to be spun down during idle periods while maintaining write capability through the solid state storage buffer, resolving the contradiction between maintaining write speed and reducing power consumption.
Solution Approach 2:
Solid state storage acts as an intermediary between the write command source and the multiple disk array. It temporarily holds data during transfer, enabling the disk array to enter passive state during idle periods while maintaining the illusion of continuous write capability to the system.
2Use of energy by moving object
If the multiple disk array is spun down during idle periods, then power consumption is reduced, but write response time increases
Solution Approach 1:
Data is pre-written to solid state storage before the multiple disk array needs to access it. This preliminary action ensures that when a write command arrives and the array is spun down, the data is already available in the solid state buffer, minimizing the time penalty of spinning up the disks.
Solution Approach 2:
The solid state storage maintains continuous write capability even when the multiple disk array is in passive state. This continuity of useful action through the intermediary solid state storage compensates for the interruptions caused by spinning the disks down and up.
3Use of energy by moving object
If a read spare drive is used to handle read operations, then the multiple disk array can spin down, but system complexity increases
Solution Approach 1:
A read spare drive maintains a synchronous copy of the data stored in the multiple disk array. This copying approach allows read operations to be handled by the single read spare drive while the multiple disk array can be spun down, reducing power consumption with relatively simple additional storage and synchronization logic.
Data Source
AI summary
Disclosed is a low power consumption storage array. Read and write cycles are separated so that a multiple disk array can be spun down during periods when there are no write requests. Cooling fans are operated with a pulse-width modulated signal in response to cooling demand to further reduce energy consumption.