Remote Copy Secondary Volume Data Transfer Optimization
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Solution Overview
Problem
Asynchronous remote copy methods in storage systems incur high processing overhead and decreased hardware utilization due to excessive data transfer, leading to reduced system performance.
Innovation Solution
The secondary storage system transfers data directly to the secondary volume without intermediate buffering when certain conditions regarding sequence numbers and restore addresses are met, reducing unnecessary data transfers and optimizing cache memory and processor efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is transferred to a buffer area (journal volume) before storing in the secondary volume during asynchronous remote copy, then data consistency is ensured, but processing overhead increases and hardware utilization efficiency decreases
Solution Approach 1:
The patent extracts the unnecessary intermediate buffer storage step from the data transfer path. By directly transferring data from the primary volume to the secondary volume through cache memory, the journal volume buffer is eliminated for cases where data consistency can be ensured through sequence number management, thereby reducing processing overhead while maintaining reliability
Solution Approach 2:
The patent performs preliminary organization of journal data in the cache memory before transfer to the secondary volume. By pre-sorting and managing data with sequence numbers in the cache, the system ensures data consistency is established before the actual transfer, eliminating the need for post-transfer buffer operations
2Reliability
If data is transferred to a buffer area (journal volume) before storing in the secondary volume during asynchronous remote copy, then data consistency is ensured, but cache memory and processor utilization efficiency decreases
Solution Approach 1:
The patent removes the journal volume buffer from the data path, allowing cache memory to be used more efficiently for active data processing rather than serving as an intermediate buffer. This extraction of the buffer function improves cache memory and processor utilization while maintaining data consistency through sequence number management
Solution Approach 2:
The cache memory is made multi-functional by using it both for temporary storage during data transfer and for final data processing. By eliminating the dedicated journal volume buffer, the cache memory handles multiple roles including data staging, sequence number management, and direct transfer preparation, improving overall system efficiency
3Stability of the object's composition
If data is transferred to a buffer area (journal volume) before storing in the secondary volume during asynchronous remote copy, then write order consistency is achieved, but system performance decreases
Solution Approach 1:
The patent performs preliminary organization of data with sequence numbers in the cache memory, establishing write order consistency before the actual transfer to the secondary volume. This pre-ordering in cache eliminates the need for buffer-based sequencing operations, improving system performance while maintaining write order stability
Solution Approach 2:
The patent uses sequence numbers as copy metadata attached to data in the cache memory. By copying and managing sequence information in the cache rather than using a separate buffer mechanism, the system maintains write order consistency with reduced processing overhead, improving overall system performance
Data Source
AI summary
According to one aspect of the invention, a storage system comprises: a plurality of storage devices; and a controller operable to manage a secondary volume, of a remote copy pair with a primary volume of another storage system, and corresponding to a portion of the plurality of storage devices. The secondary volume has a function for storing data included in journal data sent from said another storage system according to a remote copy procedure. The controller is operable to handle the journal data to be stored temporarily in a third volume corresponding to another portion of the plurality of storage devices before storing the data of the journal data to the secondary volume, if a relationship between the journal data and another journal data, which has smaller sequence number than sequence number of the journal data and is sent from said another storage system to the storage system, has a condition.