Storage System Processing Migration Method
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Solution Overview
Problem
Conventional storage system data migration methods face performance degradation due to increased data volume during storage apparatus replacement, necessitating a solution that maintains availability and performance during processing migration.
Innovation Solution
The storage system migrates write processing to a destination storage apparatus while keeping read processing with the source apparatus, then switches read processing to the destination once access data is available, allowing for efficient load management and performance preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data migration is performed using conventional methods during storage apparatus replacement, then data can be migrated between storage apparatuses, but performance degrades for a long period due to increased data volume requiring reflection of host I/O updates in both source and destination
Solution Approach 1:
The patent segments the data migration process into two independent phases: first migrating access data (metadata, mapping information) to enable the destination storage apparatus to handle write operations, then separately migrating actual host data. This segmentation allows the destination to begin processing writes without waiting for complete data replication, significantly reducing performance degradation during migration.
Solution Approach 2:
The patent performs preliminary migration of access data before migrating actual host data. By pre-establishing the access data at the destination storage apparatus, the system enables the destination to immediately begin handling write operations once data is transferred, avoiding the performance bottleneck of waiting for complete data synchronization before destination participation.
2Productivity
If access data is migrated to destination storage apparatus, then write processing can be performed at destination, but read processing must wait until access data is fully available causing performance degradation
Solution Approach 1:
The patent implements dynamic read processing that adapts based on access data availability. When access data is not yet fully migrated to the destination, read requests are dynamically routed to the source storage apparatus. Once access data is available at the destination, read requests are dynamically redirected to the destination, enabling seamless transition without prolonged performance degradation.
3Reliability
If host I/O updates are reflected in both source and destination storage apparatuses, then data consistency is maintained, but volume of data to be migrated increases adversely influencing performance
Solution Approach 1:
The patent applies local quality by having different storage apparatuses perform different functions during migration. The source storage apparatus continues handling read operations and maintains local data consistency, while the destination storage apparatus receives and processes write operations using migrated access data. This division allows data consistency to be maintained without requiring both apparatuses to simultaneously process all I/O updates.
Data Source
AI summary
A storage system includes a storage drive that stores data and a plurality of storage apparatuses, each generating access data and writing data into the storage drive, and accessing data in the storage drive using the access data, and in a case of migrating the volume together with the access data between the storage apparatuses, one responsible for the write processing on the volume being migrated to a migration destination storage apparatus at a time of migration of the access data, and one responsible for the read processing on the volume being performed by a migration source storage apparatus using the access data, and the one responsible for the read processing being migrated to the migration destination storage apparatus after the access data is available for the migration destination storage apparatus.