Introducing I-CASH, A New Disk IO Architecture

推出 I-CASH，一种新的磁盘 IO 架构

• 批准号: 1017177
• 负责人: Qing Yang
• 金额: $ 38.29万
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1017177&HistoricalAwards=false
• 关键词: Introducing; CASH; New; Disk; IO

While storage capacity and CPU processing power have experienced rapid growth in the past, improvement in data bandwidth and access times of hard disk drives (HDD) has not kept pace. As a result, the speed gap between CPUs and disk I/O is widening. Disk arrays can improve overall I/O throughput but random access latency is still very large because of mechanical operations involved. Large buffers and deep cache hierarchy can improve latency, but the access time reduction has been very limited so far because of poor data locality at the disk storage level.This proposal aims at rethinking the fundamental architecture of storage systems and makes an attempt at a paradigm shift of disk based storage architectures. The approach is to build a new storage architecture that exploits the two emerging semi-conductor technologies: flash memory SSD (solid state disks) and GPU (graphic processing unit). The new disk I/O architecture is referred to as I-CASH: Intelligently Coupled Array of SSDs and HDDs. The SSD is used to store mostly read "reference data blocks" to make best use of its high-speed random read performance. The HDD is used to store compressed delta between a current I/O block and its corresponding reference block in the SSD so that random writes are not performed on SSD during online I/O operations. The SSD and HDD are controlled by a high speed GPU that performs similarity detection, delta derivations, combining delta with reference blocks, and other necessary functions for interfacing the storage to the host OS. The idea is to leverage fast read performance of SSDs and the high speed computation of GPUs to replace and substitute, to a great extent, the mechanical operations of HDD to achieve I/O performance that is orders of magnitude better than traditional disk storage systems. Instead of working on HDD to catch up with processors' performance, which has been proven difficult if not impossible, the proposed approach lets storage systems ride the wave of the rapid advancement of multicore processors and be part of such success by trading high speed computation for low access latency. It is anticipated that the proposed project will have significantly broad and transformative impact. 1) Servers at data centers run tens and hundreds of virtual machines that generate large amount of I/Os that can take full advantage of our new storage architecture with potentially orders of magnitude performance improvement. 2) The research will engage both graduate and undergraduate students so that they are ready for the real world need. 3) The success of this research will help the economic development of the state of Rhode Island and the nation.

虽然过去的存储容量和CPU处理能力在过去经历了快速增长，但硬盘驱动器（HDD）的数据带宽和访问时间的改善尚未保持步伐。结果，CPU和磁盘I/O之间的速度差距正在扩大。磁盘阵列可以改善总体I/O吞吐量，但由于涉及机械操作，随机访问延迟仍然很大。大型缓冲区和深度高速缓存层次结构可以改善延迟，但是由于磁盘存储级别的数据局部性不佳，到目前为止，访问时间的缩短非常有限。该提案旨在重新考虑存储系统的基本架构，并尝试尝试基于磁盘的存储架构的范式转移。该方法是构建一种新的存储体系结构，该架构利用了两个新兴的半导体技术：闪存SSD（固态磁盘）和GPU（图形处理单元）。新的磁盘I/O架构称为i-Cash：智能耦合的SSD和HDD阵列。 SSD用于存储大多数读取“参考数据块”，以充分利用其高速随机读取性能。 HDD用于在当前I/O块及其相应的参考块之间存储压缩的增量，以便在线I/O操作期间未在SSD上执行随机写入。 SSD和HDD受高速GPU的控制，该高速GPU执行相似性检测，增量派生，将增量与参考块结合在一起以及将存储框架连接到主机OS的其他必要功能。这个想法是利用SSD的快速读取性能和GPU的高速计算来替换和替换HDD的机械操作来实现I/O性能，而I/O性能是比传统磁盘存储系统更好的数量级。所提出的方法并没有在HDD上赶上处理器的性能，而这被证明是很困难的，而是使存储系统能够驾驶多机处理器快速发展的浪潮，并通过将高速计算以低访问潜伏率交易来成为成功的一部分。预计拟议的项目将产生显着和变革性的影响。 1）数据中心的服务器运行数十个和数百台虚拟机，它们会生成大量的I/O，可以充分利用我们的新存储体系结构，并具有潜在的数量级性能提高。 2）研究将吸引研究生和本科生，以便他们为现实世界的需求做好准备。 3）这项研究的成功将有助于罗德岛州和国家的经济发展。