CCF--CPA: HybridStore: An Enterprise-scale Storage System Employing Solid-state Memory and Hard Disk Drives

硬盘操作中固有的机械运动为许多工作负载和存储系统提供了访问速度限制，并且正在消耗越来越多的功率。闪存克服了硬盘的一些关键限制，包括更快地访问非顺序数据和显著降低功耗。受闪存提供的这些优势和最近出现的高容量闪存驱动器的鼓舞，本研究将设计和评估一个混合系统。该系统名为HybridStore，将利用这两种介质的互补特性，在企业级存储中提供改进的性能、服务差异化和热/功率行为。HybridStore将包括一个动态数据管理解决方案，该解决方案将使可用闪存的使用适应工作负载条件。将研究提高性能的技术（例如，将非顺序内容移动到闪存，使用闪存作为写缓冲区）。研究人员将探讨闪存如何通过减少磁盘操作中固有的访问时间差异来促进改进的服务差异。最后，将研究在磁盘和闪存上选择性复制热门内容以及在热紧急情况期间将更多IO流量转移到闪存的可行性。还将探讨在不影响性能的情况下降低磁盘速度所带来的节能。研究人员将实现一个基于linux的原型直连存储混合存储系统，该系统将管理一个硬盘驱动器和一个连接到共享IO总线的sata闪存驱动器。为了探索其他混合配置（如磁盘上的闪存或RAID控制器），将实现一个名为HybridSim的综合模拟器。这些pi将通过与本研究相关的主题来加强宾夕法尼亚州立大学的研究生和本科生课程。

The mechanical movement inherent in the operation of the hard disk poses access speed limits for many workloads and storage systems are consuming increasing amounts of power. Flash memory overcomes some key limitations of the hard disk including faster access to non-sequential data and significantly lower power usage. Encouraged by these advantages offered by flash memory and the recent emergence of high-capacity flash drives, this research will design and evaluate a hybrid system. Named HybridStore, this system will exploit complementary properties of these two media to provide improved performance, service differentiation, and thermal/power behavior in enterprise-scale storage. HybridStore will comprise a dynamic data management solution that will adapt the use of available flash to workload conditions. Techniques for improving performance (e.g., moving non-sequential content to flash, use of flash as a write buffer) will be investigated. The investigators will explore how flash can facilitate improved service differentiation by reducing the variance of access times inherent in the operation of disks. Finally, the the feasibility of selected replication of popular content on disk and flash and diverting more IO traffic to flash during periods of thermal emergencies will beinvestigated. Power savings resulting from opportunities to slow down disks, without compromising performance, will also be explored. The investigators will implement a Linux-based prototype Direct-Attached Storage HybridStore system that will manage a hard disk drive and a SATA-enabled flash drive attached to the shared IO bus. To explore other hybrid configurations (such as flash on disk or RAID controller), a comprehensive simulator called HybridSim will be implemented. The PIs will enhance the graduate and undergraduatecurricula at Penn State with topics related to this research.