基于NAND闪存的固态存储系统设计及优化

发布时间：2018-04-29 16:29

本文选题：固态存储 + 闪存　；参考：《华中科技大学》2013年硕士论文

【摘要】：传统硬盘受限于机械式装置较大的访问延迟，很难满足高性能存储系统的需求，固态存储设备具有读写速度快，功耗低等优点，被越来越多地应用到存储系统中。在要求大容量高性能固态存储系统的企业级应用中，通常采用PCIe(PeripheralComponent Interconnection Express)接口的固态盘方案，但是实现方案各不兼容。NVMe(Non-volatile Memory Express)协议定义了采用PCIe总线的非易失存储子系统接口标准和命令集，通过规范操作系统和非易失存储子系统的通信协议，提高了系统的性能和兼容性。NVMe协议包含专用于非易失存储系统的命令，支持主机操作系统和固态盘协同优化。针对企业级应用对大容量高性能固态存储系统的需求，设计了基于NAND闪存的固态存储系统方案，系统包括固态存储设备驱动部分和固态存储卡部分，利用NVMe协议实现主机系统和存储卡系统的交互，通过多命令队列机制满足企业级应用高并发访问的负载特性。将固态存储卡部分划分为NVMe协议栈模块、闪存转换层模块和存储卡平台，便于系统软硬件协同开发，有利于系统升级。系统针对随机小写和映射表容量扩展性问题，采用一种子页-双页混合映射方式，，利用缓存部分映射表技术弥补大容量固态存储映射表空间过大的不足。设计了闪存转换层（FTL，Flash Translation Layer）方案，包括与子页-双页混合映射方式配合使用的缓冲区管理策略和垃圾回收算法。采用NVMe标准协议的固态存储系统方案具有很好的兼容性，通过对系统进行模拟仿真表明，这种方案能适应随机性负载较多、存储容量需求较大的企业级应用，通过优化闪存转换层，提高了写入性能，以较小的缓存映射表空间，保持了固态存储系统方案良好的扩展性。
[Abstract]:The traditional hard disk is limited by the large access delay of the mechanical device, so it is difficult to meet the demand of the high performance storage system. The solid-state storage device has the advantages of fast reading and writing speed and low power consumption, so it is applied to the storage system more and more. In the enterprise-class applications that require large capacity and high performance solid state storage systems, PCIe(PeripheralComponent Interconnection Express interfaces are usually used for solid disk applications. However, the non-volatile Memory express protocol defines the interface standard and command set of the non-volatile storage subsystem using PCIe bus. By standardizing the communication protocol between the operating system and the non-volatile storage subsystem, the communication protocol between the operating system and the non-volatile storage subsystem is defined. Improved system performance and compatibility. NVMe protocol includes commands dedicated to non-volatile storage systems and supports co-optimization of host operating systems and solid-state disks. According to the demand of enterprise applications for large capacity and high performance solid state storage system, a solid state storage system scheme based on NAND flash memory is designed. The system includes solid state storage device driver part and solid state memory card part. The NVMe protocol is used to realize the interaction between host system and memory card system, and the multi-command queue mechanism is used to satisfy the load characteristics of high concurrent access in enterprise applications. The solid state memory card is divided into NVMe protocol stack module, flash memory conversion layer module and memory card platform, which is convenient for the system hardware and software co-development and system upgrade. In order to solve the problem of random lowercase and capacity expansibility of mapping table, a subpage-two-page hybrid mapping method is adopted to compensate for the deficiency of large space of large solid state storage mapping table by using partially cached mapping table technology. A flash memory conversion layer (FTL / Flash Translation layer) scheme is designed, including buffer management strategy and garbage collection algorithm, which are used in combination with sub-page-to-two-page hybrid mapping. The solid-state storage system with NVMe standard protocol has good compatibility. The simulation results show that this scheme can adapt to the enterprise applications with more random load and larger storage capacity. By optimizing the flash memory conversion layer, the write performance is improved, and the scalability of the solid-state storage scheme is maintained with a small buffer mapping table space.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333

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