Storage Data Reduction Reporting Accuracy via Snapshot Indirect Block Tracking
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Solution Overview
Problem
Current data reduction reporting techniques in storage systems inaccurately account for space savings due to data reduction methods like pattern matching and deduplication, especially when snapshots are created, leading to a drop in reported savings and a lack of precision.
Innovation Solution
The proposed solution involves updating data reduction counters and generating snapshots to track the sharing and unsharing of indirect blocks with mapping pointers, allowing for accurate reporting of data reduction savings by distinguishing between pattern matching and deduplication contributions and excluding snap block sharing, using formulas like ilpdSaving=nPattern*primaryMappedMetaData/familyAllocatedMetaData and ildSaving=nDedup*primaryMappedMetaData/familyAllocatedMetaData.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If snapshots are created in storage systems using conventional data reduction reporting techniques, then snapshot functionality is provided, but reported space savings drop inaccurately
Solution Approach 1:
The patent segments the data reduction savings calculation into distinct components: pattern matching savings (ilpdSaving) and deduplication savings (ildSaving). Each component is calculated separately using specific formulas that account for different factors (nPattern vs nDedup, primaryMappedMetaData vs familyAllocatedMetaData). This segmentation allows accurate tracking of space savings independent of snapshot operations, resolving the contradiction by maintaining measurement precision while enabling snapshot functionality.
2Quantity of substance
If data reduction techniques are enabled to improve storage efficiency, then storage space is reduced, but reporting precision of space savings deteriorates when snapshots are involved
Solution Approach 1:
The patent implements feedback mechanisms through counters (nPattern, nDedup) that track data reduction effectiveness. These counters provide continuous feedback on actual space savings, which is then used to update reporting calculations. The feedback loop ensures that space savings reporting remains precise by continuously monitoring and adjusting based on actual data reduction performance, independent of snapshot operations.
Solution Approach 2:
The patent changes the parameters used in space savings calculations from simple before/after comparisons to weighted formulas incorporating multiple factors (nPattern*primaryMappedMetaData/familyAllocatedMetaData for pattern matching, nDedup*primaryMappedMetaData/familyAllocatedMetaData for deduplication). This parameter transformation enables accurate measurement of space savings even when snapshots create complex data relationships, resolving the contradiction between achieving storage reduction and maintaining reporting precision.
Data Source
AI summary
There is disclosed techniques for data reduction reporting in storage systems. For example in one embodiment, the techniques comprise update a counter denoting an amount of data reduction obtained when a data reduction feature associated with a data reduction requirement is enabled in the storage system when one or more allocation units in a storage system satisfy a data reduction requirement of the storage system. The techniques further comprise generating a snapshot of at least a portion of a file related to the said allocation units such that a first relationship exists when the snapshot is generated and a second relationship exists when the snapshot or the file is updated. The techniques also comprise determining a data reduction attributed to the data reduction feature based on an amount of data reduction denoted by the data reduction counter and an amount of sharing and/or unsharing of indirect blocks including mapping pointers in the relationship between the snapshot and the file.