Deduplication via Synchronized Hash Tables for Data Replication

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Solution Overview

Problem

Current data replication techniques face inefficiencies in handling duplicate data across distributed storage systems, leading to increased network bandwidth usage and computational overhead, particularly in scenarios where data deduplication is not effectively implemented.

Innovation Solution

The method involves using hash tables to identify and manage duplicate data at a per-write operation level, where a hash value is computed for each write operation, and by comparing it to existing entries, determining if it's a duplicate or unique, and transmitting only metadata for duplicates, thus eliminating redundant data transfer and maintaining synchronized hash tables across systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional data replication techniques are used to ensure data consistency across distributed storage systems, then data reliability is improved, but network bandwidth usage increases due to transmission of redundant duplicate data

Engineering Contradiction:
Improvedata consistencyVSAvoidnetwork bandwidth usage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system performs preliminary deduplication processing at the source storage system before data transmission. By computing hash values and identifying duplicate data blocks in advance, the system prepares only unique data for transmission, eliminating redundant network traffic while ensuring the destination system receives complete and consistent data sets

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention extracts and transmits only the essential components for replication - specifically metadata containing hash values and deduplication information - while leaving out redundant duplicate data blocks. This extraction approach allows the destination system to reconstruct complete data sets using the transmitted metadata and its own deduplication capabilities

Inventive Principle:
Principle #2Taking out (Extraction)

2Loss of energy

If comprehensive data deduplication processing is performed on all write operations, then network bandwidth usage is reduced by eliminating redundant transmissions, but computational overhead increases

Engineering Contradiction:
Improvenetwork bandwidth usageVSAvoidcomputational overhead
Core Design Contradiction:
Loss of energyVSUse of energy by moving object

Solution Approach 1:

The system performs partial deduplication processing by focusing computational efforts only on computing hash values for deduplication identification, rather than performing complete data comparison and analysis. This partial action approach significantly reduces computational overhead while still achieving effective duplicate detection and elimination

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The invention changes the parameter of data processing from examining entire data blocks to computing condensed hash values. This parameter transformation reduces the computational complexity from O(n) data comparison to O(1) hash computation, dramatically lowering computational overhead while maintaining deduplication effectiveness

Inventive Principle:
Principle #35Parameter changes

3Productivity

If hash tables are synchronized across distributed storage systems to enable efficient duplicate detection, then data processing efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvedata processing efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system creates and maintains simplified copies of hash table information across distributed storage systems. Instead of synchronizing entire data sets or complex metadata structures, the invention transmits and replicates only the essential hash value information needed for duplicate detection, reducing synchronization complexity while maintaining processing efficiency

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The hash table structure serves multiple functions simultaneously: it acts as a deduplication index, a replication tracking mechanism, and a data verification tool. This multi-functionality eliminates the need for separate systems for each purpose, reducing overall device complexity while enhancing data processing efficiency

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Loss of energy

If metadata is transmitted for duplicate data blocks instead of the actual data, then network bandwidth usage is reduced, but data transmission complexity increases

Engineering Contradiction:
Improvenetwork bandwidth usageVSAvoiddata transmission complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The system changes the transmission parameter from sending actual data blocks to transmitting condensed metadata containing hash values. This parameter transformation reduces transmission size from potentially large data blocks to compact metadata structures, significantly lowering network bandwidth usage while the standardized metadata format keeps transmission complexity manageable

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11231867B1Data replication using deduplication and synchronized hash tables
Publication Date: 2022.01.25 EMC IP HLDG CO LLC
  • US11231867B1 patent drawing
  • US11231867B1 patent drawing
  • US11231867B1 patent drawing

AI summary

Techniques for processing write operations may include: receiving, at a first data storage system, a first write operation that writes first data to a first device, wherein the first device is configured for replication on a second device of a second data storage system; performing first processing that determines whether the first data written by the first write operation is a duplicate of an existing entry in a first hash table of the first data storage system; responsive to determining the first data written by the first write operation is a duplicate of an existing entry in the first hash table, performing second processing; responsive to determining the first data written by the first write operation is unique and is not a duplicate of an existing entry in the first hash table, performing third processing; and transmitting the final buffer to the second data storage system.