Memory Sister Deck Synchronization to Balance PEC and Write Amplification
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Solution Overview
Problem
Performing operations on sister decks of a memory system can lead to degradation of the overall health of the memory system due to unequal program-erase cycles and increased write amplification when maintaining similar PEC counts, which affects performance and reliability.
Innovation Solution
Associating sister decks with virtual blocks and performing maintenance operations based on valid-page-count and PEC differences to synchronize operations, thereby maintaining balanced PEC counts and reducing write amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If maintenance operations are performed to maintain similar PEC counts between sister decks, then reliability is improved, but write amplification increases and performance deteriorates
Solution Approach 1:
The patent segments the memory system into multiple independent planes, where each plane can undergo maintenance operations independently. This allows the system to perform maintenance on one plane without affecting the operational status of other planes, thereby maintaining system performance while improving reliability through targeted maintenance.
Solution Approach 2:
The patent implements dynamic plane selection for maintenance operations based on real-time system state. The controller dynamically identifies which plane requires maintenance and schedules operations accordingly, allowing the system to adapt maintenance timing to minimize performance impact while ensuring reliability needs are met.
2Reliability
If maintenance operations are performed on sister decks to balance PEC counts, then reliability is improved, but write amplification increases
Solution Approach 1:
By dividing the memory system into independent planes, the patent enables selective maintenance on individual planes rather than requiring synchronized maintenance across all sister decks. This segmentation allows maintenance to be performed only where needed, avoiding unnecessary write operations and reducing write amplification while still improving reliability.
Solution Approach 2:
The patent applies partial maintenance action by performing maintenance operations on only the specific plane that requires it, rather than performing maintenance on all sister decks uniformly. This partial action approach avoids the excessive writes that would result from maintaining all decks to the same PEC level, thereby reducing write amplification while achieving the reliability benefit.
Data Source
AI summary
Methods, systems, and devices for synchronizing operations between decks of a memory system are described. In some examples, a memory system may determine a PEC difference between sister decks of physical blocks of the memory system. A memory system controller may associate the sister decks with respective virtual blocks. The controller may scan each virtual block of the memory system to determine which blocks are to be recycled, and may generate a list of virtual blocks having a VPC that satisfies a first threshold. In some cases, the controller may perform one or more threshold comparisons to determine whether to perform the maintenance operation on the first sister deck or both the first sister deck and the second sister deck.