RAID Resiliency Set Allocation Using Segmented Storage Devices

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Solution Overview

Problem

Conventional data storage systems using a mapped-RAID configuration tend to waste space when generating redundant array of independent disks (RAID) resiliency sets (RRS), as they do not efficiently utilize storage capacity, leading to unused space within the RRS.

Innovation Solution

The method involves identifying the minimum sub-RRS width based on a predefined RAID level, allocating segments from storage devices to create a maximum number of sub-RRSs, and forming the RRS from these sub-RRSs, ensuring that spare capacity is utilized and space is maximized without compromising fault tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the conventional ladder approach generates sub-RRSs from storage disks, then fault tolerance is provided, but storage space is wasted and cannot be fully utilized

Engineering Contradiction:

Improvefault toleranceVSAvoidstorage space

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent segments storage disks into multiple portions (first portion, second portion, third portion) and creates multiple sub-RRSs from these segments. This allows flexible allocation of storage segments to different sub-RRSs, maximizing space utilization while maintaining fault tolerance requirements for each sub-RRS

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a multi-dimensional allocation approach by creating sub-RRSs across different portions of storage disks rather than using a single conventional ladder approach. This dimensional expansion allows the system to utilize previously wasted space in the third portion of disks while maintaining the required fault tolerance through proper segment distribution

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the conventional ladder approach creates sub-RRSs until insufficient storage disks remain, then fault tolerance is maintained, but available storage capacity is not maximized

Engineering Contradiction:

Improvefault toleranceVSAvoidavailable storage capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the allocation parameters by defining multiple portions of storage disks and adjusting how segments are distributed across sub-RRSs. This parameter modification allows the system to maintain the minimum sub-RRS width requirement while utilizing additional storage capacity that would otherwise remain unused

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If storage disks of varying capacity are used, then storage flexibility is improved, but space utilization becomes inefficient

Engineering Contradiction:

Improvestorage flexibilityVSAvoidunused storage space

Core Design Contradiction:

Adaptability or versatilityVSLoss of substance

Solution Approach 1:

The patent applies local quality by allocating different portions of storage disks to different sub-RRSs based on their specific capacities and requirements. Each sub-RRS receives appropriate segments from storage disks, ensuring that the varying capacities of different disks are utilized effectively rather than leaving space unused

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11231859B2Providing a RAID resiliency set from a plurality of storage devices

Publication Date: 2022.01.25 EMC IP HLDG CO LLC

AI summary

A technique provides a RAID resiliency set from a plurality of storage devices. The technique involves identifying a minimum sub-RRS width based on a predefined RAID level to be enforced on the RRS. The technique further involves, based on the minimum sub-RRS width, allocating segments from the plurality of storage devices to create a maximum number of sub-RRSs. The technique further involves forming the RRS from the created maximum number of sub-RRSs.