Composite Storage Array Power Conservation via Standby Substitution
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Solution Overview
Problem
Despite the benefits of data reliability and performance provided by composite arrays of data storage devices like RAID systems, there is a need to conserve power without compromising these attributes.
Innovation Solution
A method of operating a composite array by storing data in block-level stripes with parity across at least three data storage devices, where one device is placed in a standby state, allowing the controller to manage read and write operations to conserve power while maintaining data redundancy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all data storage devices in the composite array are kept in active state, then data reliability and performance are maintained, but power consumption increases significantly
Solution Approach 1:
The patent implements dynamic power management by transitioning data storage devices between active and standby states based on operational requirements. The controller monitors I/O operations and device status, dynamically placing devices in standby state when not actively serving requests and activating them when needed, thereby optimizing the balance between power consumption and data reliability.
Solution Approach 2:
The composite array is segmented into multiple independent data storage devices that can be individually managed. The controller selectively manages power states of individual devices within the array, allowing some devices to remain active while others enter standby state, depending on current workload requirements and data access patterns.
2Use of energy by moving object
If data storage devices are placed in standby state to conserve power, then power consumption is reduced, but data access performance may be compromised
Solution Approach 1:
The system performs preliminary actions by pre-positioning data in cache memory and maintaining metadata about data locations on standby devices. When a device is activated from standby, the controller already has information about where data is stored, enabling faster data retrieval without requiring the device to fully reinitialize all its subsystems.
Solution Approach 2:
The controller acts as an intermediary between the host system and standby data storage devices. It manages the activation process, coordinates data transfer, and handles I/O operations to minimize the performance impact of devices transitioning from standby state, effectively mediating between power savings and performance requirements.
3Productivity
If the spindle motor speed is increased to improve data read rate, then data access performance improves, but power consumption increases
Solution Approach 1:
The spindle motor speed is dynamically adjusted based on actual data access requirements. The controller modulates the spindle speed to match the current I/O workload, using higher speeds only when data read rates are critical and lowering speeds during periods of low activity, thereby optimizing the trade-off between productivity and power consumption.
Solution Approach 2:
The system changes operational parameters including spindle speed, cache size allocation, and device activation thresholds based on workload analysis. By adaptively adjusting these parameters, the system achieves optimal performance for given workloads while minimizing power consumption during lower-demand periods.
Data Source
AI summary
Operating a composite array of data storage devices, such as hard disk drives, to conserve power includes storing data in block-level stripes with parity on a composite array including a controller and at least three data storage devices. The composite array includes a hot spare distributed across the data storage devices. The method further comprises placing one of the data storage devices in a standby state, operating the rest of the data storage devices in an active state, and controlling logical operations of the controller and the read and write operations of the active data storage devices to substitute for read and write operations on the standby device. For example, the controller can read redundant data on the active drives and compute data identical to the data on the standby drive to substitute for reading the standby drive. Furthermore, the controller can write a modified version of data on the standby drive to a spare block to substitute for writing to the standby drive.