Snapshot Storage Space Reclamation via Tree Data Structures
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Solution Overview
Problem
Conventional snapshot storage systems face inefficiencies in reclaiming storage space for overwritten or deleted data, leading to suboptimal performance and storage utilization.
Innovation Solution
A snapshot-enabled storage system employing a distributed architecture with replication control logic and snapshot generators, utilizing a snapshot tree data structure and block ownership bitmaps to efficiently manage data descriptors and reclaim storage space by adjusting ownership and metadata entries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional techniques are used for reclaiming storage space in sparsely-populated snapshots, then storage space can be reclaimed, but system performance is undermined due to inefficiency
Solution Approach 1:
The patent segments the snapshot storage system into distinct components: sparsely-populated snapshots containing only uniquely-written data, metadata structures organizing data by volume offset domains, and reclamation algorithms processing specific snapshot types. This segmentation enables efficient identification and reclamation of reclaimable space without scanning entire snapshot datasets, thus improving reclamation efficiency while maintaining system performance.
Solution Approach 2:
The patent implements preliminary organization of metadata into volume offset domain structures that pre-categorize data locations before reclamation is needed. This preliminary structuring allows the reclamation algorithm to quickly identify which snapshots contain reclaimable space without performing extensive scans during the actual reclamation process, thereby improving efficiency without compromising performance.
2Quantity of substance
If only uniquely-written data is stored in snapshots, then storage space utilization is optimized, but inefficient reclamation techniques undermine overall system performance
Solution Approach 1:
The patent implements feedback mechanisms where the system continuously monitors snapshot structures, metadata organization, and space utilization patterns. This feedback enables the reclamation algorithm to adaptively identify reclaimable space based on current snapshot states and historical patterns, improving reclamation efficiency while maintaining optimal storage utilization of uniquely-written data.
Solution Approach 2:
The system employs self-service reclamation algorithms that automatically identify and reclaim space from sparsely-populated snapshots without requiring manual intervention or extensive system resources. The algorithms use the pre-organized metadata structures to autonomously determine reclaimable space, improving efficiency while preserving the optimized storage utilization achieved through sparse snapshot storage.
3Productivity
If data descriptors are adjusted based on reader volume nodes, then storage space can be efficiently reclaimed, but additional metadata processing is required
Solution Approach 1:
The patent segments metadata processing into distinct phases: identification of reader volume nodes, determination of data descriptor adjustments, and execution of reclamation. This segmentation allows the system to process only relevant metadata for each phase, improving reclamation efficiency while managing complexity through structured, modular processing steps.
Solution Approach 2:
The system performs preliminary identification and categorization of reader volume nodes before adjusting data descriptors. This preliminary action organizes the metadata processing workload, enabling efficient reclamation by pre-determining which descriptors need adjustment and which snapshots are readers, thereby reducing the complexity of the actual reclamation execution phase.
Data Source
AI summary
An apparatus in an illustrative embodiment comprises at least one processing device comprising a processor coupled to a memory. The apparatus is configured to maintain a snapshot tree data structure having a plurality of volume nodes corresponding to respective ones of (i) a root volume and (ii) multiple snapshots related directly or indirectly to the root volume. The apparatus is further configured to determine a set of data descriptors for a given volume offset, to determine a set of reader volume nodes that are readers of a corresponding data item based at least in part on the set of data descriptors, to adjust one or more of the data descriptors in the set of data descriptors based at least in part on the set of reader volume nodes, and to reclaim storage space previously allocated to the data item responsive to the adjusting of the one or more data descriptors.