Storage Translation Layer for ZNS Drive Write Shaping
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Solution Overview
Problem
High-density NAND storage devices face issues with low endurance and performance due to increasing write amplification factor (WAF), requiring sequential writes and complicating application adaptations, which increases customer costs and reduces drive lifetime.
Innovation Solution
A storage translation layer is implemented between physical devices and user logical space, using a high-endurance drive like Persistent Memory (PM) with a write-shaping buffer to stage writes and manage them efficiently, reducing WAF and eliminating the need for direct NAND device writes, while allowing standard addressing for applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-density NAND storage devices are used to increase storage capacity, then storage density is improved, but write amplification factor increases leading to lower endurance and performance
Solution Approach 1:
A persistent memory cache tier is introduced as an intermediary between the host and the NAND capacity tier. The memory controller manages this tiered structure, using the persistent memory as a write-shaping buffer that absorbs write operations and shapes them into sequential writes to the NAND drive, thereby reducing write amplification and improving endurance while maintaining high storage capacity
Solution Approach 2:
The storage system is segmented into two distinct tiers: a persistent memory cache tier for handling write operations and a NAND capacity tier for long-term storage. This segmentation allows each tier to operate optimally - the persistent memory handles random writes with high endurance, while the NAND drive handles sequential writes for capacity storage, resolving the contradiction between capacity and endurance
2Reliability
If zoned namespace drives are used to improve endurance, then drive lifetime is improved, but sequential write requirement increases device complexity and limits applicability
Solution Approach 1:
The persistent memory cache tier acts as a mediator that translates arbitrary write patterns from applications into sequential write patterns required by the zoned namespace drive. The memory controller manages this translation transparently, allowing applications to use standard addressing methods while the intermediary handles the sequentialization required for ZNS optimization
Solution Approach 2:
Write operations are staged in the persistent memory cache tier before being transferred to the NAND capacity tier. This preliminary action allows the system to accumulate writes and shape them into sequential patterns before committing to the ZNS drive, eliminating the need for applications to perform preliminary sequentialization
3Productivity
If application-specific adaptations are implemented to handle non-sequential workloads, then workload performance is improved, but development cost and complexity increase
Solution Approach 1:
The persistent memory cache tier provides universal functionality that handles all types of workloads (sequential, random, mixed) without requiring application-specific adaptations. The memory controller implements a universal write-shaping mechanism that works across different workload patterns, eliminating the need for separate optimized paths for different application types and reducing development complexity
4Adaptability or versatility
If standard addressing methods are used with ZNS drives, then application compatibility is improved, but write amplification factor increases reducing performance
Solution Approach 1:
The persistent memory cache tier serves as an intermediary layer that accepts standard addressing methods from applications while translating these into optimized sequential write operations for the ZNS drive. This intermediary function maintains application compatibility without sacrificing write performance, as the cache tier handles the translation and optimization transparently
Data Source
AI summary
Systems, apparatuses, and methods provide for a memory controller to manage a tiered memory including a zoned namespace drive memory capacity tier. For example, a memory controller includes logic to translate a standard zoned namespace drive address associated with a user write to a tiered memory address write. The tiered memory address write is associated with the tiered memory including the persistent memory cache tier and the zoned namespace drive memory capacity tier. A plurality of tiered memory address writes are collected, where the plurality of tiered memory address writes include the tiered memory address write and other tiered memory address writes in the persistent memory cache tier. The collected plurality of tiered memory address writes are transferred from the persistent memory cache tier to the zoned namespace drive memory capacity tier, via an append-type zoned namespace drive write command.