Cache Data Migration During Power Failure
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Solution Overview
Problem
Conventional storage systems with caches face data loss during long-term power failures due to limited battery capacity, as the cache cannot be continuously refreshed, leading to data loss in case of power outages.
Innovation Solution
A method and system that involves receiving configuration information from a CPU during a power failure, establishing a mapping relationship between cache and storage device addresses, and sending a signaling message to migrate data from the cache to the storage device, ensuring data backup and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cache is powered on by a spare battery during power failure to ensure data is not lost, then data protection is improved, but the cache cannot be refreshed continuously due to limited battery capacity, leading to data loss in long-term power failures
Solution Approach 1:
The patent extracts the data backup function from the cache memory and transfers it to the storage device. During power failure, the system migrates data from the cache to the storage device, which has no power consumption requirements for data retention. This separates the temporary high-speed storage function (cache) from the permanent data retention function (storage device), allowing the storage device to handle long-term data protection without relying on battery capacity.
Solution Approach 2:
The patent implements preliminary action by establishing a mapping relationship between cache addresses and storage device addresses before data migration is needed. The system prepares the storage device in advance by creating a mapping table that specifies which cache locations correspond to which storage locations, enabling rapid data migration when power failure occurs without requiring real-time address translation during the critical backup period.
2Loss of energy
If the storage system cuts off all services during power failure to conserve power, then power consumption is reduced, but data protection capability is limited because the cache cannot be refreshed
Solution Approach 1:
The patent extracts the data retention requirement from the cache and relocates it to the storage device. By doing so, the cache can be powered down completely during power failure without losing data protection capability, since the storage device assumes the data retention function. This allows the system to minimize power consumption while maintaining data protection through the storage device's non-volatile nature.
Solution Approach 2:
The patent introduces an intermediary mechanism (the mapping relationship and data migration process) that bridges the cache and storage device during power failure. The mapping relationship acts as a mediator that enables the system to transition data from the powered-down cache to the storage device, ensuring data protection without requiring continuous power to the cache or other system services.
3Speed
If the cache is used to respond to host requests faster, then response speed is improved, but data loss occurs during power failure due to lack of continuous refresh
Solution Approach 1:
The patent segments the storage system into two distinct functional components: the cache for high-speed temporary storage and the storage device for permanent data retention. During normal operation, the cache provides fast response speeds. During power failure, the system activates the storage device to retain data, separating the speed function from the reliability function to allow each to optimize independently without compromising the other.
Solution Approach 2:
The patent implements preliminary action by pre-establishing a mapping relationship between cache addresses and storage device addresses. This preparation enables the system to rapidly migrate data from the cache to the storage device during power failure without requiring complex real-time address translation, thus maintaining data integrity while preserving the cache's high-speed performance during normal operation.
Data Source
AI summary
A method, device and system for storing data in a cache in case of power failure are disclosed. The method includes: in case of power failure of a storage system, receiving configuration information from a central processing unit (CPU); establishing a mapping relationship between an address of data in the cache and an address in a storage device according to the configuration information; sending a signaling message that carries the mapping relationship to the cache, so that the cache migrates the data to the storage device according to the signaling message.