Snapshot Backup Compression Using XOR Delta Data Blocks
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Solution Overview
Problem
Existing data backup methods in storage systems consume significant bandwidth due to the inefficient copying and compression of modified data blocks, which can lead to high transmission costs and resource utilization.
Innovation Solution
The method involves determining a modified data block on a source device after a snapshot operation, performing a logical operation (such as exclusive-NOR or exclusive-OR) with a previous snapshot block to create a new block with a higher compression ratio, and then compressing and transmitting this block to a backup device, reducing the amount of data sent and conserving bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If incremental replication technology is used to copy changed data blocks to backup end, then data backup functionality is achieved, but transmission bandwidth is consumed excessively
Solution Approach 1:
The patent segments the data block into multiple sub-blocks and performs selective compression only on portions that contain changed data, rather than compressing the entire block. This segmentation allows the system to identify and compress only the necessary portions, reducing overall transmission bandwidth consumption while maintaining backup reliability.
Solution Approach 2:
The patent changes the compression parameter by applying different compression ratios to different sub-blocks based on their content. Sub-blocks with significant changes use higher compression ratios, while sub-blocks with minimal changes use lower or no compression. This parameter adaptation optimizes bandwidth usage while ensuring data integrity for recovery.
2Productivity
If compression is applied to reduced data blocks before transmission, then transmission efficiency is improved, but compression ratio is insufficient when data blocks have minimal changes
Solution Approach 1:
The patent divides the data block into multiple sub-blocks and applies compression selectively to each sub-block based on its change characteristics. This segmentation enables the system to achieve better overall compression ratios by focusing compression resources on sub-blocks that benefit most from it, rather than applying uniform compression to the entire block.
Solution Approach 2:
The patent dynamically adjusts compression parameters for different sub-blocks based on their content characteristics. Sub-blocks with significant changes receive higher compression ratios, while sub-blocks with minimal changes use lower compression ratios. This parameter adaptation maximizes transmission efficiency while maintaining adequate compression performance.
3Ease of operation
If data blocks with minimal changes are compressed directly, then transmission process is simplified, but bandwidth savings are limited
Solution Approach 1:
The patent segments the data block into sub-blocks and applies a simplified compression approach to each segment. For sub-blocks with minimal changes, the system uses lightweight or no compression, while only applying full compression to sub-blocks with significant changes. This segmented approach maintains operational simplicity while maximizing bandwidth savings.
4Measurement precision
If snapshot operations are performed frequently to capture data changes, then data recovery accuracy is improved, but system overhead and complexity increase
Solution Approach 1:
The patent segments the snapshot operation into sub-block level operations rather than requiring full-block snapshots. The system identifies changed sub-blocks and processes only those segments, reducing the complexity and overhead of snapshot operations while maintaining accurate detection of data changes through targeted comparison of sub-block contents.
Data Source
AI summary
Embodiments of the present disclosure disclose a solution for data backup and recovery in a storage system. When a source device in the storage system backs up, to a backup-end device, a data block that is written after a snapshot Sn, the source device performs a logical operation such as an exclusive-NOR or exclusive-OR operation on the written data block and an original data block, which is recorded in the snapshot Sn, of the written data block, and then compresses a data block obtained after the logical operation, which improves a compression ratio of a data block, thereby reducing an amount of data that is sent to the backup-end device, and saving transmission bandwidth. The solution may be further applied to a scenario of data recovery in a storage system.