Virtual Block Data Stripe Refresh for SSD Read Errors
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Solution Overview
Problem
Existing solid state drive (SSD) systems face issues with write amplification and reduced lifespan due to complete data refresh operations, which introduce unnecessary P/E cycles and open block erases, leading to decreased reliability and increased read errors.
Innovation Solution
Implementing a selective data stripe refresh method that identifies and refreshes only the affected portion of a virtual block (VB) instead of the entire block, reducing write amplification and avoiding unnecessary open block erases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complete data refresh operations are performed on virtual blocks, then read errors are mitigated and reliability is improved, but write amplification increases and P/E cycles are unnecessarily consumed
Solution Approach 1:
The patent segments the virtual block into multiple data stripes and performs refresh operations on only the affected stripe containing the read error, rather than refreshing the entire virtual block. This segmentation allows selective refresh of problematic portions while preserving other data stripes, thereby reducing unnecessary write amplification and P/E cycles while still mitigating read errors in the affected region.
Solution Approach 2:
The patent applies local quality by identifying the specific data stripe with read errors and applying refresh operations only to that localized portion. Instead of uniform treatment of the entire virtual block, the system targets the specific stripe with degraded quality (read errors), optimizing the balance between reliability improvement and energy loss reduction.
2Reliability
If complete data refresh operations are performed on virtual blocks, then reliability is improved, but device lifespan is reduced due to increased P/E cycles
Solution Approach 1:
By segmenting the virtual block into data stripes and refreshing only the affected stripe, the patent reduces the total number of P/E cycles performed on the device. This selective approach extends device lifespan by minimizing wear on non-affected blocks while still maintaining reliability through targeted refresh operations on problematic stripes.
3Reliability
If complete data refresh operations are performed on virtual blocks, then read errors are mitigated, but unnecessary open block erases occur
Solution Approach 1:
The patent applies local quality by identifying and refreshing only the specific data stripe with read errors, avoiding unnecessary open block erases in other stripes. This localized approach eliminates harmful side effects while maintaining the beneficial effect of read error mitigation in the affected region.
Data Source
AI summary
In some implementations, a controller may detect a read error associated with data obtained based on a request from a host device. The controller may identify a data frame, of a virtual block, that stores the data. The controller may perform scan operations or host read operations on the virtual block. The controller may determine whether the read error is localized to less than a portion of the virtual block, based on performing the scan operations or the host read operations. The controller may perform a data refresh of a data stripe of the virtual block based on determining whether the read error is localized to less than the portion of the virtual block, wherein the data stripe includes the data, and wherein the data refresh is performed without performing a data refresh of other data stripes of the virtual block.