Logical Drive Duplication Without Snapshot Storage
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Solution Overview
Problem
Existing logical drive duplication methods require a snapshot logical drive, leading to increased storage space requirements and duplication time due to the need for multiple steps and additional writes, which slows down the duplication process and causes drive wear.
Innovation Solution
A method and apparatus that sequentially copy data from a source logical drive to a destination logical drive, determining and handling write requests by copying data to the destination drive before executing the write, thereby eliminating the need for a snapshot logical drive and reducing data reads/writes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a snapshot logical drive is used during duplication, then data consistency is maintained, but storage space requirements increase and duplication time increases
Solution Approach 1:
The patent extracts and eliminates the snapshot logical drive from the duplication process. Instead of creating a snapshot to maintain data consistency, the system directly copies data from the source logical drive to the destination logical drive while handling write requests inline, thereby removing the unnecessary storage component while maintaining consistency through alternative means
Solution Approach 2:
The patent implements preliminary action by copying data blocks to the destination logical drive before processing subsequent write requests. When a write request is received for a block that has already been copied, the system copies the updated data block again before allowing the write, ensuring consistency without requiring a snapshot drive
2Reliability
If a snapshot logical drive is used during duplication, then data consistency is maintained, but duplication time increases
Solution Approach 1:
The patent removes the snapshot logical drive from the duplication architecture, eliminating the time required to create, maintain, and process snapshots. The system directly copies data blocks and handles write requests in a more efficient inline manner, significantly reducing duplication time while maintaining data consistency
Solution Approach 2:
The patent enables continuous duplication operation without the interruptions and overheads associated with snapshot management. The system continuously copies data blocks and processes write requests in a streamlined fashion, maintaining useful duplication action throughout without the time losses inherent in snapshot-based approaches
3Reliability
If multiple steps and additional writes are performed during duplication, then data consistency is ensured, but drive wear increases
Solution Approach 1:
The patent extracts and eliminates the unnecessary intermediate steps and additional writes that would occur with snapshot-based duplication. By directly copying data blocks and handling write requests in a streamlined inline manner, the system reduces the total number of write operations to the destination drive, thereby reducing drive wear while maintaining data consistency
Data Source
AI summary
There is provided a method of duplicating a logical drive. The method includes sequentially copying data from a source logical drive to a destination logical drive and determining whether a write request is received to a data area on the source logical drive which has not yet been copied to the destination logical drive. If a write request is detected, the data at the write-requested data area is copied to the destination logical drive prior to executing the write request. By providing such a method, the destination logical drive can be used as the change-data store while in the process of the duplication operation, removing the need for a snapshot logical drive in the duplication process. This results in improvements in duplication speed and reduces drive wear due to the reduced number of data reads/writes.