RAID Cache Backup via Nonvolatile Memory Parity
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Solution Overview
Problem
RAID systems face challenges in ensuring data integrity and reliability during power outages due to limited backup unit capacity, leading to increased costs and reduced processing power after power restoration.
Innovation Solution
A backup method that writes cache data from volatile memory to nonvolatile memory, generates parity data, verifies errors, and rewrites data as needed, using a one-to-one connection between backup units and controller modules to ensure power supply and reduce the write-through state duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacity of the backup unit is increased, then the reliability of data guarantee is improved, but the cost and size of the RAID system increase
Solution Approach 1:
The patent writes cache data to nonvolatile memory in advance before power outage occurs, so that when power is lost, the data is already preserved and does not require large backup units to maintain reliability during extended outages
Solution Approach 2:
The patent creates a copy of cache data in nonvolatile memory as a backup, allowing the system to recover without needing large capacitive backup units. The nonvolatile memory serves as a duplicate storage location that preserves data integrity
2Reliability
If the capacity of the backup unit is increased, then the reliability of data guarantee is improved, but the size of the RAID system increases
Solution Approach 1:
Data is written to nonvolatile memory before power failure, eliminating the need for large backup units and reducing overall system size while maintaining reliability
Solution Approach 2:
By copying data to nonvolatile memory, the system achieves reliable data protection without requiring additional large-capacity backup components, thus reducing system size
3Productivity
If power is restored after outage, then the RAID system can resume operation, but the write-through state reduces processing power significantly
Solution Approach 1:
Cache data is written to nonvolatile memory before power outage, so when power is restored, the system does not need to maintain a prolonged write-through state, reducing the time productivity is reduced
Solution Approach 2:
The system uses parity data to verify data integrity in nonvolatile memory and automatically rewrites corrupted data, allowing the system to exit write-through state faster and resume normal processing power
4Reliability
If error in cache data cannot be recovered by parity data, then data integrity is compromised, but rewriting in different area increases nonvolatile memory usage
Solution Approach 1:
The nonvolatile memory is divided into multiple areas, and when error recovery fails, data is rewritten to a different area segment, preserving data integrity while managing memory resources efficiently
Solution Approach 2:
Error correction and rewriting operations are applied locally to specific data areas rather than the entire memory, maintaining data integrity in affected regions while minimizing overall memory usage impact
Data Source
AI summary
A backup method makes a backup of cache data to a nonvolatile memory by using a controller, the cache data being stored in the volatile memory. The backup method includes writing the cache data stored in the volatility memory in a selected area of the nonvolatile memory, generating party data by operating the parity operations between each of the predetermined parts of the cache data in the volatile memory, verifying whether an error found in the part of the cache data in the nonvolatile memory can be recovered by using the parity data, and rewriting the part of the cache data when the error found in the part of the cache data in the nonvolatile memory cannot be recovered by using the parity data in an area of the nonvolatile memory different from the selected area.