Scalable Parity Protection for Disk Failure Reconstruction

Solution Overview

Problem

Current RAID schemes face scalability challenges due to increased data storage density and disk failure rates, particularly during long rebuild times, as they struggle to efficiently handle multiple disk failures without significant CPU-intensive computations and complex implementations.

Innovation Solution

A method is introduced that calculates multiple sets of parity units by processing data units cached in a storage system's cache memory, using virtual shifts to facilitate disk failure reconstruction, allowing for efficient reconstruction of data units even when multiple disks fail, by calculating additional sets of parity units responsive to varying shifts and destaging them to disks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional RAID schemes are used to protect against multiple disk failures, then data reliability is improved, but device complexity and CPU overhead increase significantly

Engineering Contradiction:

Improvedata reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the protection mechanism into multiple independent parity sets (first parity set, second parity set, third parity set), each handling different failure scenarios. This segmentation allows the system to protect against multiple disk failures while maintaining manageable complexity for each individual parity calculation, as each set can be computed and stored independently

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary action by pre-calculating and storing multiple parity sets before any disk failures occur. The first parity set is calculated from original data, the second parity set is calculated from data combined with the first parity, and the third parity set is calculated from data combined with both previous parity sets. This preliminary preparation enables rapid recovery without intensive real-time computations when failures occur

Inventive Principle:

Principle #10Preliminary action

2Reliability

If traditional RAID schemes are used to protect against multiple disk failures, then data reliability is improved, but CPU overhead increases significantly

Engineering Contradiction:

Improvedata reliabilityVSAvoidCPU overhead

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary action by pre-calculating and storing multiple parity sets before any disk failures occur. The first parity set is calculated from original data, the second parity set is calculated from data combined with the first parity, and the third parity set is calculated from data combined with both previous parity sets. This preliminary preparation enables rapid recovery without intensive real-time computations when failures occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the protection mechanism into multiple independent parity sets (first parity set, second parity set, third parity set), each handling different failure scenarios. This segmentation allows the system to protect against multiple disk failures while maintaining manageable complexity for each individual parity calculation, as each set can be computed and stored independently

Inventive Principle:

Principle #1Segmentation

3Quantity of substance

If storage density is increased to improve capacity, then storage capacity is improved, but rebuild time increases leading to higher risk of additional failures

Engineering Contradiction:

Improvestorage capacityVSAvoidrebuild reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent performs preliminary action by pre-calculating and storing multiple parity sets before any disk failures occur. The first parity set is calculated from original data, the second parity set is calculated from data combined with the first parity, and the third parity set is calculated from data combined with both previous parity sets. This preliminary preparation enables rapid recovery without intensive real-time computations when failures occur

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9471429B2Scalable protection scheme for protecting destaged data units

Publication Date: 2016.10.18 INFINIDAT LTD

AI summary

A method for disk failure protection, the method may include calculating a first set of parity units by processing a first group of sets of data units that are cached in a cache memory of a storage system; calculating a second set of parity units by processing the first group of sets of data units; wherein the calculating of the second set of parity units is responsive to a first shift that was virtually introduced between each set of data units of the first group of sets of data units; and destaging the first group of sets of data units and the first and second sets of parity units to the first group of disks.