Storage System Defragmentation by Reference Frequency

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Solution Overview

Problem

Deduplication storage systems experience a decrease in I/O performance due to fragmentation, which is not efficiently addressed by existing defragmentation techniques that do not consider data content.

Innovation Solution

A storage system that includes a data storage controlling part to track reference frequency of data and a defragmentation processing part to move and store data based on this frequency, optimizing data placement to reduce fragmentation and maintain performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If defragmentation is executed on all regions in a deduplication storage system, then fragmentation is overcome, but I/O performance decreases due to high I/O load

Engineering Contradiction:
Improvedata distribution uniformityVSAvoidI/O performance
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating defragmentation treatment based on data characteristics. It identifies regions with high duplication rates and exempts them from defragmentation, while only defragmenting regions with low duplication rates. This localized approach optimizes the balance between overcoming fragmentation and maintaining I/O performance by applying defragmentation selectively rather than uniformly across all storage regions.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If deduplication storage system operates for a long period, then storage capacity increases, but free space becomes fragmented and I/O performance decreases

Engineering Contradiction:
Improvestored data volumeVSAvoidfree space continuity
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent implements preliminary action by proactively managing free space through selective defragmentation before fragmentation severely impacts performance. It continuously monitors duplication rates and initiates defragmentation operations on low duplication rate regions to maintain free space continuity, preventing the accumulation of fragmentation that would otherwise degrade I/O performance over time.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If existing defragmentation techniques are used, then fragmentation is addressed, but data content characteristics are not considered leading to inefficient defragmentation

Engineering Contradiction:
Improvedata distributionVSAvoiddefragmentation efficiency
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by using duplication rate as a key parameter to determine defragmentation targets. It dynamically identifies regions with low duplication rates and directs defragmentation operations to these specific regions, rather than treating all regions uniformly. This parameter-based approach significantly improves defragmentation efficiency by focusing computational resources on regions that actually benefit from defragmentation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9367256B2Storage system having defragmentation processing function
Publication Date: 2016.06.14 NEC CORP
  • US9367256B2 patent drawing
  • US9367256B2 patent drawing
  • US9367256B2 patent drawing

AI summary

A storage system according to the present invention includes: a data storage controlling part that stores data into a storage device and, when storing other data of the same data content as the data, refers to the already stored data as the other data; and a defragmentation processing part that moves and stores storage target data stored in an area set as a defragmentation range within a predetermined region of the storage device, into another region of the storage device. The data storage controlling part stores reference frequency that is frequency of referring to data as other storage target data. The defragmentation processing part, depending on the reference frequency of the data, stores the data into an area to become a defragmentation range later within another region of the storage device.