Storage Controller Logging for Cache Directory Update Overhead
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Solution Overview
Problem
Existing storage systems face performance degradation due to increased processing loads on processors, networks, and disks when small updates with a large number of updates occur, particularly for cache directory information, leading to inefficient management of control information and cache data.
Innovation Solution
A storage system and method that includes separate handling of first-type and second-type control information, where first-type information is logged individually and second-type information is consolidated before logging, reducing the overall log size and processing load, while ensuring high reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control information is updated frequently with small update sizes, then the system maintains high reliability through redundant configuration, but the processing load on processor, network, and disk increases significantly
Solution Approach 1:
The patent segments control information into two types: first-type control information that requires individual logging for critical updates, and second-type control information that can be consolidated with other updates. This segmentation allows the system to maintain reliability for critical operations while reducing overhead for less critical updates by batching them together.
Solution Approach 2:
The patent merges multiple small updates of second-type control information into a single consolidated log entry. Instead of creating separate log entries for each small update, the system combines them into one log record, significantly reducing the number of log write operations and improving processor, network, and disk efficiency while maintaining system reliability.
2Reliability
If individual logs are created for each control information update, then data integrity is maintained, but the total amount of management information and transfer volume increases
Solution Approach 1:
The patent combines multiple small control information updates into a single consolidated log entry, reducing the total volume of log data that needs to be managed and transferred. The consolidation process maintains data integrity by properly tracking and recording all changes within the unified log structure.
Solution Approach 2:
The patent changes the parameter of log organization from individual per-update logs to consolidated batch logs. This parameter change reduces the quantity of log data while maintaining the essential integrity information through structured consolidation that preserves the ability to track and verify all changes.
Data Source
AI summary
A storage controller (for example, a storage control unit 123) can execute log creation processing of, when a write request is processed and control information or cache data is updated, adding a header to the updated data to create an update log and storing the update log in a log buffer. In the log creation processing when first-type control information (normal control information) is updated, the storage controller adds a log header to each piece of updated first-type control information to create an update log (normal log 132), and in the log creation processing when second-type control information (cache directory) is updated, the storage controller creates one consolidated log (consolidated log 137) as an update log related to a plurality of pieces of second-type control information.