Storage Drive Power Management via Redundancy Group Segmentation

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Solution Overview

Problem

Storage systems face challenges in maintaining responsiveness while in a power-saving state, as existing technologies do not effectively manage power consumption without compromising performance.

Innovation Solution

A storage system with a redundancy group of storage drives that can selectively switch to a power-saving state, allowing data restoration from other drives within the group to maintain responsiveness during read requests, thereby reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If storage drives are set to power saving state, then power consumption is reduced, but responsiveness to read requests deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidresponsiveness

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The storage system divides storage drives into two distinct groups: active drives that remain operational and power-saving drives that are in a low-power state. This segmentation allows the system to maintain responsiveness through active drives while reducing overall power consumption through the power-saving group, directly resolving the contradiction between power savings and responsiveness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The controller acts as an intermediary that manages data retrieval between power-saving drives and the host. When a read request targets a power-saving drive, the controller retrieves data from active drives instead, mediating between the power-saving state and the need for responsive data access, thus maintaining responsiveness without requiring power-saving drives to be fully active.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If more storage drives are kept active, then responsiveness is improved, but power consumption increases

Engineering Contradiction:

ImproveresponsivenessVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

Different storage drives are assigned different operational states based on local needs: some drives maintain full functionality (active state) while others operate in a reduced-capacity state (power-saving state). This local differentiation optimizes the balance between responsiveness and power consumption by activating only the necessary portion of the storage system.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically changes the operational parameter (power state) of storage drives based on system needs. Drives can transition between active and power-saving states, allowing the system to adjust power consumption levels while maintaining responsiveness through the controller's ability to retrieve data from active drives on demand.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If all storage drives are in power saving state, then power consumption is minimized, but system reliability deteriorates

Engineering Contradiction:

Improvepower consumptionVSAvoidsystem reliability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system prepares for potential failures by maintaining active drives as a cushion or backup resource. When power-saving drives are in use, active drives stand ready to provide data if needed, providing beforehand protection against data loss or access failures, thus maintaining reliability while allowing power-saving drives to remain in low-power state.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The controller can discard the assumption that power-saving drives are immediately accessible and instead recover data from active drives when needed. This approach treats power-saving drives as optional resources that can be discarded from immediate access considerations, with recovery of data functionality provided through active drives, maintaining reliability without compromising power savings.

Inventive Principle:

Principle #34Discarding and recovering

Data Source

PatentUS11385815B2Storage system

Publication Date: 2022.07.12 HITACHI VANTARA LTD

AI summary

A storage system includes a redundancy group formed of storage drives that stores host data and redundant data in a distributed manner, and a controller that controls access to the redundancy group. The controller is configured to: select, from among the storage drives in the redundancy group, a part of the storage drives in an upper limit number equal to or smaller than a redundancy level of the redundancy group, and set the part of the storage drives to a power saving state; receive, from a host, a read request with respect to a target storage drive in the redundancy group; and restore, when the target storage drive is in the power saving state, target data corresponding to the read request from data collected from a part of the storage drives different from the target storage drive in the redundancy group, and return the target data to the host.