Online Storage Aggregate Shrinkage Through Data Relocation
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Solution Overview
Problem
Existing storage appliances do not support reducing the provisioned storage capacity of a disk or aggregate, leading to wasted space and inefficiencies in cloud-based storage systems.
Innovation Solution
A method is introduced to identify a shrink region within a storage aggregate, relocate valid data from this region to other disks, and either remove the source disk or replace it with a smaller disk after mirroring the data, thereby reducing the aggregate's provisioned capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If storage capacity is increased dynamically by adding disks to the aggregate, then storage capacity is improved, but device complexity increases
Solution Approach 1:
The patent inverts the conventional one-way growth model by enabling dynamic shrinkage of storage capacity. Instead of only adding disks to increase capacity, the system can now remove disks from the aggregate to reduce capacity, allowing bidirectional adjustment of storage resources based on actual needs.
Solution Approach 2:
The patent implements dynamic adjustment of storage capacity by enabling online disk removal from aggregates. The system dynamically monitors storage usage and can proactively shrink capacity by removing underutilized disks, transforming the static storage architecture into a flexible, adaptive system that responds to changing storage demands in real-time.
2Loss of energy
If storage capacity is reduced by removing disks from the aggregate, then storage space waste is reduced, but system reliability may be compromised
Solution Approach 1:
The patent applies preliminary action by performing data relocation and mirroring before disk removal. The system identifies disks for removal in advance, relocates their data to other aggregate disks, and creates mirrors to ensure data redundancy is maintained or improved before actually removing the disks, thus preventing data loss and maintaining reliability.
Solution Approach 2:
The patent uses copying by creating mirror images of data on remaining disks before removing source disks. This copying mechanism ensures that data redundancy is preserved or enhanced during the shrinkage operation, as the mirrored copies provide backup data that maintains system reliability even after the original disks are removed.
3Quantity of substance
If data is relocated from the shrink region to other regions, then storage capacity is reduced, but data loss risk increases
Solution Approach 1:
The patent implements feedback mechanisms that continuously monitor data relocation progress and verify data integrity. The system tracks the relocation process in real-time, validates data consistency between source and destination regions, and provides feedback to ensure complete and accurate data transfer before confirming disk removal, thereby preventing data loss.
Solution Approach 2:
The patent uses copying by creating precise data copies during relocation and verification processes. The system copies data blocks from the shrink region to destination regions and validates the copies to ensure data integrity, maintaining accurate data representations throughout the relocation process to prevent information loss.
Data Source
AI summary
Systems and methods for reducing the provisioned storage capacity of a disk or aggregate of disks of a storage appliance while the storage appliance continues to serve clients are provided. According to one embodiment, the size of the aggregate may be reduced by shrinking the file system of the storage appliance and removing a selected disk from the aggregate. When an identified shrink region is less than the entire addressable PVBN space of the selected disk, the file system may be shrunk by relocating valid data from the shrink region of the selected disk to one or more regions outside of the shrink region, mirroring data of the selected disk from outside of the shrink region to a smaller disk added to the aggregate, and then removing the selected disk after the mirrors are in sync, thereby reducing the provisioned storage capacity of the aggregate by the difference in size between the selected disk and the smaller disk.