NVRAM Failure Domain Segmentation for Storage Reliability

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Solution Overview

Problem

Current data storage systems face challenges in efficiently detecting and remediating failures, particularly in non-volatile random access memory (NVRAM) devices, which can lead to data loss and system instability as storage capacity increases.

Innovation Solution

The implementation of advanced failure detection mechanisms within NVRAM devices, including fine-grained failure domains and metadata chunks with checksums, coupled with proactive rebuild strategies and redundancy schemes like erasure coding, allows for timely identification and recovery of failures, ensuring data integrity and system reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If storage system capacity is increased, then storage capacity utilization is improved, but failure detection and remediation complexity increases

Engineering Contradiction:
Improvestorage capacityVSAvoidfailure detection and remediation complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The NVRAM device is divided into multiple failure domains, each independently monitored for failures. This segmentation allows the system to manage failures at a granular level rather than treating the entire device as a single unit, reducing the complexity of failure detection and remediation in large-capacity storage systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements continuous monitoring of failure domains with automatic feedback mechanisms that detect failures and trigger remediation actions. This automated feedback loop reduces the complexity of managing failure detection and remediation in high-capacity storage systems by eliminating manual intervention.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If fine-grained failure domains are implemented, then failure detection precision is improved, but device complexity increases

Engineering Contradiction:
Improvefailure detection precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The NVRAM device is divided into multiple failure domains, each independently monitored for failures. This segmentation allows the system to manage failures at a granular level rather than treating the entire device as a single unit, reducing the complexity of failure detection and remediation in large-capacity storage systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each failure domain is independently monitored and can autonomously detect its own failures without requiring complex system-wide analysis. This self-service approach simplifies the overall device complexity while maintaining high detection precision at the failure domain level.

Inventive Principle:
Principle #25Self-service

3Reliability

If proactive rebuild strategies are implemented, then system reliability is improved, but loss of time increases

Engineering Contradiction:
Improvesystem reliabilityVSAvoidrebuild time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs proactive rebuild operations when failures are detected in failure domains, restoring data redundancy before actual data loss occurs. This preliminary action approach improves system reliability by preventing failures from propagating, while the targeted nature of failure domain-specific rebuilds minimizes the time required compared to full-device rebuilds.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Rebuild operations are performed locally at the failure domain level rather than system-wide, allowing redundant data to be restored in the specific affected areas. This localized approach maintains high system reliability while reducing rebuild time by limiting the scope of remediation to only the necessary portions of the storage system.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11256587B2Intelligent access to a storage device
Publication Date: 2022.02.22 PURE STORAGE INC
  • US11256587B2 patent drawing
  • US11256587B2 patent drawing
  • US11256587B2 patent drawing

AI summary

A method of failure detection in a storage system is performed by the storage system. The method includes detecting a failure in a nonvolatile random access memory device that is in or coupled to a storage device having storage memory. The storage system has multiple NVRAM devices and multiple storage devices that have storage memory. The method includes taking a portion or all of the NVRAM device offline. Taking a portion or all of the NVRAM device offline is responsive to detecting the failure. Taking a portion or all of the NVRAM device off-line is while keeping online the storage memory of the storage device, sufficient ones of the NVRAM devices, and sufficient ones of the storage devices to provide reliable access to data and metadata in the storage system.