Snapshot Replication Using Differential Block Maps
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Solution Overview
Problem
Existing snapshot technologies are incompatible with replication processes due to features like SmartSnap, which inefficiently copy all data changes, including invalid or 'garbage' values, leading to performance degradation and unnecessary storage usage.
Innovation Solution
Adapting snapshot technologies to track changes in both previously-allocated and newly-allocated storage units, only replicating valid data changes and avoiding the storage of invalid data, thereby optimizing performance and storage efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If snapshot technologies copy all data changes including invalid or garbage values, then replication completeness is ensured, but storage efficiency deteriorates and performance degrades
Solution Approach 1:
The patent extracts only the valid data changes from the data set, separating them from invalid or garbage values. The snapshot mechanism identifies and copies only the necessary data blocks that contain valid changes, excluding redundant or invalid data from the replication process.
Solution Approach 2:
Instead of copying all data changes (excessive action), the patent implements partial copying by selectively identifying and replicating only the valid data changes. This partial action approach reduces storage waste while maintaining replication completeness for valid data.
2Reliability
If snapshot technologies copy all data changes including invalid or garbage values, then replication completeness is ensured, but replication performance deteriorates
Solution Approach 1:
The patent extracts only the valid data changes from the data set, separating them from invalid or garbage values. The snapshot mechanism identifies and copies only the necessary data blocks that contain valid changes, excluding redundant or invalid data from the replication process.
Solution Approach 2:
Instead of copying all data changes (excessive action), the patent implements partial copying by selectively identifying and replicating only the valid data changes. This partial action approach reduces storage waste while maintaining replication completeness for valid data.
3Measurement precision
If snapshot technologies track changes in all storage units, then change detection accuracy is improved, but storage efficiency deteriorates
Solution Approach 1:
The patent applies local quality by treating previously-allocated and newly-allocated storage units differently. For previously-allocated units, it tracks changes to maintain accuracy. For newly-allocated units, it determines whether they contain valid data before tracking, applying selective monitoring based on the local characteristics of each storage unit.
Solution Approach 2:
The patent extracts only the valid data changes from the data set, separating them from invalid or garbage values. The snapshot mechanism identifies and copies only the necessary data blocks that contain valid changes, excluding redundant or invalid data from the replication process.
Data Source
AI summary
A replication process using snapshots to maintain information regarding changes made to a production data set following a point in time. In some embodiments, the production data set may be a file system and the snapshot may store information relating to changes made to both previously-allocated and newly-allocated data blocks. When a change is made to a previously-allocated data block, the original contents for the data block may be copied to a save volume prior to being overwritten by the new data, while for a newly-allocated data block no data may be copied to the save volume. An entry may also be created in a map identifying each changed data block. A replication process may then read the block map to identify data blocks storing new data to should be replicated to a replication data set, such that the replication data set remains a copy of the production data set.