Storage Scrubbing Scheduling via Conformal Prediction

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Solution Overview

Problem

Large data storage systems face performance degradation due to frequent scrubbing of physical storage devices, which increases wear and load, while infrequent scrubbing may delay detection of media errors. Existing methods do not differentiate between storage devices based on health, leading to inefficient resource allocation.

Innovation Solution

Implement a method to determine the relative eligibility of physical storage devices for scrubbing using conformal prediction analysis, ranking them based on health scores, and scheduling scrubbing frequency according to predicted workload and health categories, thereby reducing unnecessary scrubbing and optimizing resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If frequent scrubbing is performed on all physical storage devices, then media errors are detected timely, but system performance degrades and device wear increases

Engineering Contradiction:
Improvedetection of media errorsVSAvoidsystem performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating scrubbing frequency based on individual device health status. Instead of uniform scrubbing across all devices, the system assigns different scrubbing frequencies to different physical storage devices according to their specific health conditions, thereby optimizing the balance between error detection and performance impact.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically changes the scrubbing frequency parameter based on device health metrics. By monitoring health indicators and adjusting the scrubbing interval parameter accordingly, the system reduces scrubbing frequency for healthy devices while maintaining high frequency for deteriorating devices, thus resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If frequent scrubbing is performed on all physical storage devices, then media errors are detected timely, but device wear increases

Engineering Contradiction:
Improvedetection of media errorsVSAvoiddevice lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by differentiating scrubbing frequency based on individual device health status. Instead of uniform scrubbing across all devices, the system assigns different scrubbing frequencies to different physical storage devices according to their specific health conditions, thereby optimizing the balance between error detection and performance impact.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system performs partial scrubbing action by selectively applying full scrubbing only to devices that need it most (those with deteriorating health), while applying reduced or no scrubbing to healthy devices. This partial action approach minimizes unnecessary wear on healthy devices while maintaining adequate monitoring for at-risk devices.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If infrequent scrubbing is performed, then system performance is maintained, but detection of media errors is delayed

Engineering Contradiction:
Improvesystem performanceVSAvoiddetection of media errors
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system dynamically changes the scrubbing frequency parameter based on device health metrics. By monitoring health indicators and adjusting the scrubbing interval parameter accordingly, the system reduces scrubbing frequency for healthy devices while maintaining high frequency for deteriorating devices, thus resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If uniform scrubbing frequency is applied to all devices, then management is simplified, but resource allocation is inefficient

Engineering Contradiction:
Improvescrubbing managementVSAvoidresource allocation efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating scrubbing frequency based on individual device health status. Instead of uniform scrubbing across all devices, the system assigns different scrubbing frequencies to different physical storage devices according to their specific health conditions, thereby optimizing the balance between error detection and performance impact.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11899633B2Managing storage device scrubbing
Publication Date: 2024.02.13 EMC IP HLDG CO LLC
  • US11899633B2 patent drawing
  • US11899633B2 patent drawing
  • US11899633B2 patent drawing

AI summary

From among physical storage devices (PSDs) of a storage system, a set of two or more of the PSDs that are eligible for scrubbing may be determined; and from among the set, a relative eligibility of the PSDs may be determined. Conformance prediction analysis may be applied to determine the set and the relative eligibility of PSDs of the set. The conformance prediction analysis may determine a scrubbing eligibility classification (e.g., label), and a confidence value for the classification, which may serve as the relative eligibility of the PSD. The eligible PSDs may be ranked in an order according to determined confidence values, and may be further classified according to such order. The future workload of the storage system may be forecasted, and the scrubbing of PSDs may be scheduled based on the forecasted workload of the system and the relative eligibilities of the set of PSDs.