Doubly Mapped RAID Node Failure Mitigation

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Solution Overview

Problem

Conventional data storage systems face inefficiencies in utilizing storage space, particularly in large real clusters, where smaller amounts of data are underutilized, and there is a need for more granular storage solutions to manage failures in real nodes without data loss.

Innovation Solution

The implementation of a doubly mapped redundant array of independent nodes (RAID) system, which allows for data redundancy and flexible node topology, enabling the creation of smaller logical storage groups within larger real clusters, and employs reserved extents to mitigate real node failures by redistributing data across other nodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a large real cluster is used for bulk data storage, then storage capacity is improved, but storage efficiency deteriorates due to underutilization when smaller amounts of data need to be stored

Engineering Contradiction:

Improvestorage capacityVSAvoidstorage efficiency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent divides the large real cluster into multiple virtual storage groups, each with customizable storage capacity. This segmentation allows different portions of the cluster to be allocated to different virtual groups based on specific storage needs, enabling efficient utilization of storage resources whether small or large amounts of data need to be stored.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a virtualization layer that adds a logical dimension to the physical storage cluster. By creating virtual storage groups that can be independently configured and managed, the system allows flexible allocation of storage space without being constrained by the physical hardware configuration, thus improving storage efficiency while maintaining large capacity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If smaller real groups are created to improve storage efficiency, then storage efficiency is improved, but computer resource usage deteriorates due to inefficient support for multiple smaller groups

Engineering Contradiction:

Improvestorage efficiencyVSAvoidcomputer resource usage

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent creates virtual storage groups that can be dynamically allocated and configured to serve different storage needs. The underlying physical infrastructure remains shared and universal, allowing multiple virtual groups to utilize the same hardware resources efficiently. This multi-functionality enables the system to support various storage configurations without duplicating physical resources, thus improving storage efficiency while minimizing computer resource usage.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If data is distributed across multiple nodes for redundancy, then reliability is improved, but system complexity deteriorates in managing node failures and data redistribution

Engineering Contradiction:

Improvedata accessibilityVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a virtualization layer as an intermediary between the physical storage nodes and the data. This intermediary manages the complexity of data distribution, redundancy, and failure recovery automatically. When node failures occur, the virtualization layer handles data redistribution transparently, maintaining data accessibility without requiring complex manual intervention, thus improving reliability while managing system complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If reserved extents are employed to mitigate real node failures, then reliability is improved, but storage efficiency deteriorates due to reserved space that cannot be used for data storage

Engineering Contradiction:

Improvefailure mitigationVSAvoidstorage efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic reserved extents that can be automatically allocated and deallocated based on system conditions. When failures occur, reserved extents are activated to provide redundancy. When the system is operating normally, these extents can be dynamically reallocated for data storage, thus improving storage efficiency while maintaining the capability for failure mitigation. This dynamic approach resolves the contradiction between reliability and storage efficiency.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11449399B2Mitigating real node failure of a doubly mapped redundant array of independent nodes

Publication Date: 2022.09.20 EMC IP HLDG CO LLC

AI summary

Mitigating the effects of a real node failure in a doubly mapped redundant array of independent nodes, e.g., doubly mapped cluster is disclosed. In response to a change in an accessibility to data stored on an extent of a real storage device of a real node of a real cluster, wherein the extent of the real storage device corresponds to a portion of a mapped storage device of a mapped node of a doubly mapped cluster, substituting a reserved extent of a real storage device for the extent of the real storage device. The substituting the reserved extent of the real storage device can correspond to a change in a topology of the doubly mapped cluster, wherein the change in the topology comprises replacing the portion of the mapped storage device with a substitute portion of a mapped storage device that corresponds to the replacement extent of the real storage device. The changed topology can enable writing of data to the substituted portion of a mapped storage device that can cause writing of corresponding data to the reserved extent of the real storage device.