SSD Parity Mode Switching for QLC Data Retention
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Solution Overview
Problem
Portable SSDs with Quad-Level Cell (QLC) technology face high read errors and reduced data retention reliability when idle for extended periods, and existing firmware policies like Patrol Read and Random Interval Neighbor Check become less effective, leading to data integrity issues.
Innovation Solution
A method and storage device that dynamically adjust Write Amplification Factor (WAF) and fill factor thresholds based on current parity mode values to optimize data writing, using a table of parity mode values to enhance data retention and error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If QLC technology is used to increase storage capacity, then storage density is improved, but data retention reliability deteriorates
Solution Approach 1:
The patent dynamically changes the code rate parameter based on storage fill factor and write amplification factor. When fill factor exceeds a threshold, the system transitions from a first code rate to a second code rate, adjusting the balance between storage efficiency and data retention reliability to match actual usage conditions.
Solution Approach 2:
The patent implements dynamic code rate adjustment rather than using a fixed code rate. The code rate is adaptively changed based on real-time monitoring of fill factor and write amplification factor, allowing the system to optimize between storage capacity and data retention reliability according to actual operating conditions.
2Use of energy by moving object
If SSD remains idle for extended periods to save power, then energy consumption is reduced, but data retention reliability deteriorates
Solution Approach 1:
The patent applies preliminary error correction by writing parity data along with user data during the initial write operation. This preemptive error correction capability ensures that even if the device remains idle for extended periods, the stored data can be recovered using the pre-written parity information without requiring frequent power-on operations.
3Reliability
If higher parity mode is used to improve error correction, then data integrity is improved, but write amplification factor increases
Solution Approach 1:
The patent dynamically adjusts the code rate parameter based on fill factor and write amplification factor thresholds. When fill factor is low, a lower code rate (higher parity overhead) is used to ensure data integrity. When fill factor increases, the system transitions to a higher code rate (lower parity overhead), automatically optimizing the balance between error correction capability and write amplification.
Data Source
AI summary
The present disclosure provides storage device and method for writing data in the storage device. The method for writing data in a storage device includes determining, by the storage device, a Write Amplification Factor (WAF) value and a fill factor value associated with the storage device in response to a write request, fetching, by the storage device, a current parity mode value of the storage device, determining, by the storage device, a WAF threshold and a fill factor threshold associated with the current parity mode value, determining, by the storage device, whether to change the current parity mode value to a higher parity mode value of a plurality of parity mode values based on the WAF threshold, the WAF value, the fill factor threshold, and the fill factor value, and writing, by the storage device, data in a storage area of the storage device based on results of the determining.