Storage Drive Hot-Swap via Difference Information
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Solution Overview
Problem
Existing storage system technologies require significant time and effort to replace components with drives installed, as they necessitate copying all data to a new node, disrupting operations.
Innovation Solution
A storage system configuration that allows drives to be moved between nodes without stopping operations by generating and using difference information to restore data on the target drive, utilizing existing drives effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all data is copied to a new node for component replacement, then data integrity is maintained, but replacement time and operational disruption increase significantly
Solution Approach 1:
Instead of copying all data from the old drive to the new drive, the patent applies partial action by only copying the difference information (changed data blocks) identified through checksum comparison. This dramatically reduces the copying time and operational disruption while still maintaining complete data integrity, as the majority of data blocks that haven't changed don't need to be transferred.
Solution Approach 2:
The patent extracts only the essential information needed for data verification (checksum values) and transfers minimal data (difference information) rather than moving the entire dataset. By taking out only the changed portions identified through checksum comparison, the system achieves efficient drive replacement with minimal time loss.
2Adaptability or versatility
If drives are moved between nodes, then configuration flexibility improves, but data consistency and operational continuity become challenging
Solution Approach 1:
The patent performs preliminary actions by calculating and storing checksum values for all data blocks before drive replacement occurs. This pre-computed verification information enables the system to quickly identify which data blocks have changed during the move operation, ensuring data consistency can be verified and restored if needed without disrupting operational continuity.
Solution Approach 2:
The patent implements feedback mechanisms by using checksum comparisons to verify data consistency after drive movement. The system continuously monitors and compares data integrity through checksum validation, providing feedback that ensures configuration changes maintain data consistency and operational reliability throughout the drive replacement process.
Data Source
AI summary
A storage system comprises nodes and drives, and includes at least one mounting area to install the drives. A node manages a parity group constituted of the plurality of drives; generates, in a case where a target drive that is installed in a first mounting area and that belongs to a first parity group is to be moved from the first mounting area to a second mounting area, difference information regarding a storage area where data was written into the target drive during a period in which the target drive is moved from the first mounting area to the second mounting area; and restore data written into the storage area by using data stored in other drives than the target drive that belongs to the first parity group based on the difference information, and write the data into the target drive that has been moved to the second mounting area.