Storage System Intermediate Parity for Scale-Out Expansion
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Solution Overview
Problem
Existing storage systems face challenges in maintaining high capacity efficiency when expanding RAID configurations, particularly in scale-out systems where bandwidth between nodes is limited, leading to slow data migration and inefficient node addition processes.
Innovation Solution
A storage system that updates RAID configurations by generating intermediate parity from data blocks and parity blocks within nodes, transferring this parity to other nodes, and reconfiguring stripes to reduce data migration and improve capacity efficiency during node addition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nodes are sequentially added to expand RAID configuration in a scale-out system, then system capacity is increased, but data migration time increases due to limited bandwidth between nodes
Solution Approach 1:
The patent segments the parity calculation process by introducing intermediate parity blocks that are calculated and transferred separately from the main data migration process. This allows the expansion operation to be divided into smaller, parallelizable steps that reduce the burden on inter-node bandwidth.
Solution Approach 2:
The patent uses intermediate parity blocks as mediators in the data migration process. These intermediate parity blocks serve as temporary storage that facilitates the transition from old to new RAID configurations without requiring direct, high-volume data transfers between all nodes simultaneously.
2Productivity
If all data is relocated to expand stripe configuration, then capacity efficiency is improved, but the expansion process takes long time due to narrow bandwidth between nodes
Solution Approach 1:
The patent performs preliminary actions by calculating and transferring intermediate parity blocks before completing the full data relocation. This allows the system to prepare for the expansion in advance, reducing the critical path time of the overall expansion operation.
Solution Approach 2:
The patent implements partial action by allowing the RAID expansion to proceed with intermediate parity blocks rather than requiring complete data relocation. The system can achieve functional expansion with partial data movement, and the remaining data can be migrated later without blocking the expansion process.
Data Source
AI summary
Each of multiple nodes has a processor, a memory, and a storage region. In a process of updating a stripe, the processors generate an intermediate parity from a data block included in a first node and a parity block included in the first node and included in the stripe to be processed, transfer the intermediate parity to a second node, cause the intermediate parity to be stored as a parity in a block of the second node, and configure the stripe with the data block from which the intermediate parity has been generated, the block storing the parity, and a data block included in a node other than the first and second nodes and included in the stripe to be processed.