ZNS SSD Parity Layout for Single-Cycle Dual-Failure Protection

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Solution Overview

Problem

Current RAID systems with solid-state drives (SSDs) face inefficiencies in computing parity, particularly in resource usage, especially when dealing with dual drive failures, as they often require extensive processing cycles and dedicated parity drives.

Innovation Solution

The technology efficiently generates horizontal and vertical parity for zoned namespace SSDs (ZNS SSDs) in a RAID configuration by using a single parity drive and distributing parity data within each SSD, reducing the need for additional processing cycles and dedicated parity drives through simultaneous data transfer and XOR operations within the same cycle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional RAID systems compute parity using dedicated parity drives and multiple processing cycles, then data protection reliability is improved, but resource consumption and processing time increase

Engineering Contradiction:

Improvedata protectionVSAvoidprocessing efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges the computation of horizontal and vertical parity into a single processing cycle by simultaneously calculating both parity types from the same data stripes. The system computes horizontal parity across data drives and vertical parity across parity drives concurrently, eliminating the need for separate processing cycles and reducing overall computation time while maintaining RAID-6 level data protection

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent enables parity drives to serve dual functions: storing horizontal parity data and computing vertical parity data. This multi-functionality allows the same hardware resources to handle multiple parity computation tasks, improving resource utilization and reducing the need for additional dedicated parity drives

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple dedicated parity drives are used for RAID-6 protection, then data protection against dual drive failures is improved, but device complexity and resource consumption increase

Engineering Contradiction:

Improvedual drive failure protectionVSAvoidparity drive configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a multi-functional parity drive architecture where the same parity drives are used for both horizontal and vertical parity operations. This eliminates the need for separate dedicated parity drives for each parity type, reducing device complexity while maintaining RAID-6 protection capabilities against dual drive failures

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines horizontal and vertical parity storage functions into a unified parity drive structure. By merging these functions, the system achieves dual parity protection with fewer drives, simplifying the overall device configuration and reducing resource consumption

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If parity computation is performed continuously with cache line reloading, then data processing throughput is maintained, but resource consumption and processing time increase

Engineering Contradiction:

Improvedata processing throughputVSAvoidprocessing cycles

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent maintains continuous data processing throughput by eliminating cache line reloading during parity computation. The system processes data continuously through optimized memory access patterns and register-based computation, keeping the data processing pipeline full without interruption while reducing overall processing time

Inventive Principle:

Principle #20Continuity of useful action

4Measurement precision

If significant processing power and memory are allocated for parity computation, then parity accuracy is improved, but resource consumption increases

Engineering Contradiction:

Improveparity accuracyVSAvoidcomputational resource consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces traditional memory-intensive parity computation with a register-based computational approach. By using processor registers instead of main memory for intermediate parity calculations, the system maintains high parity accuracy while significantly reducing memory access overhead and computational resource consumption

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11797377B2Efficient parity determination in zoned solid-state drives of a storage system

Publication Date: 2023.10.24 NETAPP INC

AI summary

Methods and systems for a storage environment are provided. One method includes copying a data unit from a first temporary storage location corresponding to each zoned solid-state drive (ZNS SSD) of a first ZNS SSD set of a storage system to a first XOR module, while determining a first partial horizontal parity using the data unit stored in the first temporary storage location; and determining a vertical parity for each ZNS SSD of the first ZNS SSD set using the data unit provided to the first XOR module in a current cycle and vertical parity determined from a previous cycle.