温度感知的三维闪存存储系统可靠性和性能优化技术研究

By stacking flash cells in vertical direction, 3D flash memory achieves significant density improvement and lithography cost reduction, which is rapidly replacing planar flash memory as the storage medium in cloud storage and data center. However, the overheating phenomenon seriously affects the reliability and I/O performance of the 3D flash memory storage system, which leads to the serious hindrance to the further development and large-scale application of 3D flash memory. Therefore, in this project, aiming at improving performance and reliability for temperature-aware 3D flash memory storage system, we will solve the key scientific problems of 3D flash memory under high operating temperature. In this project, we will research the 3D flash memory storage system from these three aspects as following: 1) For reliability optimization, we will research on new thermal throttling technology to both guarantee storage QoS and reliability. 2) For read performance optimization, we will exploit a temperature variation aware read redirection on 3D flash memory. 3) For write performance optimization, we will conduct research on cross-layer thermal data management in 3D flash memory storage system. Finally, we will implement these solutions in the 3D flash simulator with real applications. Thus, we build a stable, efficient and reliable 3D flash memory storage system, which promotes the further development and application of 3D flash memory.

三维闪存固态硬盘通过在垂直方向上堆叠闪存存储元，获得了存储密度的提升和制造成本的下降，正快速取代二维闪存成为云存储及数据中心的主流存储介质。但是，三维闪存运行温度对数据可靠性和读写性能的影响巨大，高温急剧地降低三维闪存的可靠性、引起读写性能的波动，导致三维闪存的进一步发展和大规模应用受到严重阻碍。因此，本项目以增强三维闪存可靠性、提升存储系统性能为目标，旨在解决三维闪存运行温度过热情况下存储系统面临的关键科学问题。具体研究内容包括：1）在可靠性优化方面，保障存储服务质量的前提下优化过热问题，提出请求差异感知的细粒度热节流策略；2）在读性能优化方面，设计基于温度差异感知的重定位读机制；3）在写性能优化方面，展开温度感知的热数据跨层管理研究。最终，在验证平台上实现并以实际应用来验证和完善提出的解决方案，实现一个高效、稳定且可靠的三维闪存存储系统，推进三维闪存研究的进一步发展及其应用。

近年来闪存存储获得高速发展，这其中三维闪存固态硬盘因其高效地提升存储密度，成为闪存制造业最具潜能的发展方向。但是，在三维闪存固态硬盘中，运行的温度对数据可靠性和存储性能具有巨大的影响。因此，本项目从以下三个方面展开研究：通过研究三维闪存中新的可靠性特征，展开研究可靠性优化研究；从三维闪存的读性能展开研究，设计和实现考虑温度差异的重定位读机制；从三维闪存的写性能展开研究，设计和实现考虑温度影响的写性能优化研究。通过以上三个方面地深入研究，本项目取得了一系列成果，包括依托本项目已经发表论文10篇，提交发明专利3项，培养一批高水平的学术人才。本项目的研究内容和研究成果能为当前高速发展的非易失性存储业提供实际的关键技术支撑。