Storage System Performance Evaluation Using Z-Score Deviation Analysis

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Solution Overview

Problem

Current methods for evaluating system performance focus on averages, neglecting deviations that can lead to unacceptable latency spikes, resulting in an incomplete picture of system behavior.

Innovation Solution

A method that samples data points over a period, calculates deviation values by subtracting system specifications, averages these deviations, calculates standard deviation, and divides by the standard deviation to produce a modified performance value accounting for operational characteristics, providing a more comprehensive assessment of system performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If average performance is used to evaluate system performance, then overall system performance is captured, but deviations and latency spikes are ignored

Engineering Contradiction:
Improveperformance evaluation accuracyVSAvoidsystem consistency
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transforms the performance evaluation from using raw performance values to using standardized z-scores. By converting performance measurements into standardized units that account for both mean and standard deviation, the system can identify deviations from expected performance behavior. This parameter transformation enables detection of latency spikes and inconsistencies that would be hidden in average-only metrics.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If only average performance metrics are collected, then data collection is simple, but performance consistency and latency variations are not detected

Engineering Contradiction:
Improveevaluation efficiencyVSAvoidperformance deviation detection
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where performance data is continuously collected, standardized, and compared against expected performance characteristics. The z-score calculation provides immediate feedback about whether performance deviations are statistically significant, enabling the system to identify consistency issues without requiring complex analysis of every individual measurement.

Inventive Principle:
Principle #23Feedback

3Reliability

If detailed performance sampling and deviation calculation is performed, then performance consistency is evaluated, but computational complexity increases

Engineering Contradiction:
Improveperformance consistency evaluationVSAvoidevaluation process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent simplifies the evaluation process by transforming raw performance data into standardized z-scores using well-established statistical formulas. This parameter transformation reduces complex performance evaluation to straightforward calculations involving mean and standard deviation, making the process computationally efficient while maintaining the ability to detect performance inconsistencies.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10853221B2Performance evaluation and comparison of storage systems
Publication Date: 2020.12.01 EMC IP HLDG CO LLC
  • US10853221B2 patent drawing
  • US10853221B2 patent drawing
  • US10853221B2 patent drawing

AI summary

Described embodiments provide storage system evaluation and comparison processes. An aspect includes sampling data points for a workload running on system over a sampling period. The data points indicate a performance metric with respect to operational characteristics of the system. An aspect further includes subtracting a system specification value from each of the averaged sampled data points, thereby producing deviation values reflecting a deviation of the sampled data points from the system specification value. An aspect also includes averaging the sampled data points, calculating a standard deviation of the averaged sampled data points, and dividing the variance value by the standard deviation, thereby producing a modified performance value that accounts for a deviation in the operational characteristics of the system over the sampling period.