Weibull Modulus-Based Read Ahead Cache Control for Restore Workloads

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Solution Overview

Problem

Data protection restore operations are hindered by the need to read and cache large amounts of data, leading to inefficiencies and increased costs due to reading unnecessary data, especially when access patterns switch between sequential and non-sequential.

Innovation Solution

The implementation of a modulus-based approach, utilizing a Weibull statistical probability distribution to dynamically enable or disable read ahead caching based on the shape parameter, adjusting thresholds according to the access pattern's trend, thereby optimizing restore operations by managing when to use read ahead caching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If read ahead caching is enabled to improve restore speed, then restore operation speed is improved, but unnecessary data is read and cached increasing cost and inefficiency

Engineering Contradiction:
Improverestore operation speedVSAvoidunnecessary data read
Core Design Contradiction:
SpeedVSLoss of substance

Solution Approach 1:

The patent applies dynamics by making the read ahead cache state (enabled/disabled) dynamic rather than static. The system continuously monitors access patterns and adjusts the cache state in real-time based on whether the pattern is sequential or non-sequential, allowing the system to adapt to changing data access requirements during restore operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback by monitoring access patterns during restore operations and using this information to control the read ahead cache. The system detects whether access patterns are sequential or non-sequential and feeds this information back to the cache control mechanism, which then adjusts cache behavior accordingly to optimize performance and reduce unnecessary data reading.

Inventive Principle:
Principle #23Feedback

2Loss of time

If read ahead caching is enabled to reduce restore time, then restore operation time is reduced, but cost increases due to reading unnecessary data from cloud

Engineering Contradiction:
Improverestore operation timeVSAvoidcost
Core Design Contradiction:
Loss of timeVSLoss of energy

Solution Approach 1:

The system dynamically adjusts read ahead cache behavior based on real-time access pattern analysis. When access patterns indicate sequential reading, the cache is enabled to reduce restore time; when non-sequential patterns are detected, the cache is disabled to avoid reading unnecessary data and incurring additional cloud costs.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from access pattern monitoring to control cache operations. By continuously analyzing whether data access is sequential or non-sequential and feeding this information back to the cache control logic, the system optimizes the balance between restore speed and data reading cost, preventing unnecessary cloud data reads that would increase expenses.

Inventive Principle:
Principle #23Feedback

3Productivity

If read ahead caching is used to optimize restore performance, then restore efficiency is improved, but device complexity increases due to cache management

Engineering Contradiction:
Improverestore efficiencyVSAvoidcache management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system implements self-service by automatically detecting access patterns and making decisions about cache state without requiring complex external management. The restore operation itself provides the information needed (access patterns) to control the cache, creating a self-regulating system that improves efficiency while keeping management complexity relatively low.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The feedback mechanism simplifies cache management by using straightforward access pattern detection (sequential vs. non-sequential) to control cache behavior. This feedback-based approach avoids complex predictive algorithms or manual configuration, achieving improved restore efficiency through a relatively simple control logic that monitors and reacts to actual data access patterns.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11630743B2Managing restore workloads using Weibull modulus
Publication Date: 2023.04.18 EMC IP HLDG CO LLC
  • US11630743B2 patent drawing
  • US11630743B2 patent drawing
  • US11630743B2 patent drawing

AI summary

One example method includes determining a modulus such as a Weibull modulus for a recovery operation. Enablement and disablement of a read ahead cache are performed based on the modulus. The modulus is a linearization of a cumulative distribution function, where failures correspond to non-sequential accesses and successes correspond to sequential accesses.