Mapped RAID Group Creation During Extent Pool Expansion

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Solution Overview

Problem

Existing storage technologies face challenges in efficiently expanding storage capacity and making it accessible during the process of adding new drives to an extent pool, as the traditional shuffling and RAID group creation process is time-consuming, leading to prolonged unavailability of expanded storage space.

Innovation Solution

The method involves generating an empty Mapped RAID group and incrementally mapping RAID extents to it while shuffling the extent pool, allowing for partial accessibility and faster creation of new RAID groups, even before the shuffling process is complete.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If traditional shuffling and RAID group creation process is used, then storage capacity is expanded, but the time required to make the expanded storage space accessible is prolonged

Engineering Contradiction:

Improvestorage capacityVSAvoidtime to access expanded storage space

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The system performs preliminary actions by creating an empty Mapped RAID group structure in advance and initiating the shuffling process before the RAID group is fully populated. This allows the storage system to prepare the framework for expanded capacity ahead of time, so that as extents are shuffled and mapped during the expansion process, the storage space becomes accessible much faster than waiting for complete shuffling to finish.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The expansion process is segmented into independent phases: creating the empty Mapped RAID group structure, shuffling extents in the background, and progressively mapping RAID extents to the Mapped RAID group. This segmentation allows different parts of the expansion process to proceed in parallel, with the structure creation happening independently from the data shuffling, thereby reducing the time to make storage accessible.

Inventive Principle:

Principle #1Segmentation

2Productivity

If RAID extent mapping is performed during shuffling, then storage capacity expansion speed is improved, but system complexity increases

Engineering Contradiction:

Improvestorage capacity expansion speedVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The Mapped RAID group serves as an intermediary structure between the extent pool and the final RAID groups. This intermediary allows the system to decouple the complex shuffling process from the RAID group creation process, enabling RAID extents to be mapped progressively as extents become available during shuffling, without requiring the entire shuffling process to complete first.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adjusts the mapping process by monitoring the shuffling progress and progressively mapping RAID extents to the Mapped RAID group as extents become available. This dynamic approach allows the system to adapt the expansion speed to the shuffling rate, maximizing productivity without overwhelming the system with excessive complexity.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10852966B1System and method for creating mapped RAID group during expansion of extent pool

Publication Date: 2020.12.01 EMC IP HLDG CO LLC

AI summary

A method, computer program product, and computer system for receiving, by a computing device, one or more drives added to an extent pool of storage devices. An empty Mapped RAID group may be generated. A plurality of extents in the extent pool may be shuffled. A RAID extent may be mapped to the empty Mapped RAID group, wherein the RAID extent is mapped to the empty Mapped RAID group while shuffling the plurality of extents in the extent pool.