RAID Array Transformation via Storage Pool Extents
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Solution Overview
Problem
Conventional RAID storage systems lack the ability to dynamically change parameters such as the number of disks, disk size, and RAID level without deleting and re-creating the array, leading to reduced effective capacity and performance, especially in large-scale systems, due to the requirement of statically reserved extents.
Innovation Solution
A method and system that reserve a small number of extents in a storage pool to manage RAID transformations, allowing data to be migrated from one array configuration to another without affecting the logical data structure, using reserved and free extents to write data to a second array configuration with different parameters, thereby enabling dynamic changes to RAID parameters without data destruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If statically reserved extents are required on each array for transformation, then array transformation capability is enabled, but effective capacity is reduced
Solution Approach 1:
A storage pool acts as an intermediary between multiple RAID arrays, centralizing extent management. The storage pool contains reserved extents that can be dynamically allocated to any array needing transformation, eliminating the need for each array to maintain its own static reservations. This mediator approach enables array transformations while preserving the effective capacity of individual arrays.
Solution Approach 2:
The storage pool serves multiple functions: it stores data for various arrays, maintains reserved extents for transformation operations, and provides a centralized resource pool that can be dynamically allocated. This universal resource pool replaces the need for dedicated reserved extents on each array, improving overall system utilization while maintaining transformation capabilities.
2Adaptability or versatility
If multiple extents are reserved on each array for transformation, then transformation flexibility is improved, but storage utilization deteriorates
Solution Approach 1:
The storage pool serves as a centralized intermediary that manages all reserved extents for transformation operations across multiple arrays. Instead of each array maintaining separate reservations, the storage pool consolidates these resources, allowing dynamic allocation and significantly improving overall storage utilization while maintaining transformation flexibility.
Solution Approach 2:
Individual array-specific reserved extents are merged into a single centralized storage pool. This consolidation combines previously fragmented reservations into a unified resource that can be efficiently allocated to any array needing transformation, eliminating duplicate reservations and improving storage utilization across the system.
3Quantity of substance
If arrays are expanded by adding disks using conventional methods, then capacity is increased, but new disks do not contribute to parity overhead
Solution Approach 1:
The system enables dynamic reconfiguration of RAID arrays by transforming array parameters through data migration to temporarily reserved extents. When expanding capacity, new disks can be integrated into the array configuration through transformation operations, allowing them to properly contribute to parity overhead rather than being added as simple capacity extensions.
Solution Approach 2:
The invention enables changing array parameters (such as number of disks, RAID level) through controlled transformation processes. When expanding capacity, the array parameters are updated to reflect the new configuration, ensuring that all disks including newly added ones properly participate in parity calculations and contribute to array reliability.
Data Source
AI summary
Aspects of the present invention relate to an apparatus and corresponding method that includes reading data from a first portion of an in-use redundant array of independent disks (RAID), wherein the first portion of the in-use RAID is arranged according to a first array configuration having at least a first parameter. One or more reserved extents in a storage pool is used to store at least a first portion of the data for writing to the in-use RAID. One or more free extents in the storage pool and/or in the in-use RAID is used to store at least a second portion of the data for writing to the in-use RAID. The data is written to a second portion of the in-use RAID. The second portion of the in-use RAID is arranged according to a second array configuration having at least a second parameter.