A New Spectrum of Hierarchical Storage Architectures for High Performance Disk I/Os

这项研究正在调查几种创新的磁盘I/O体系结构的设计和性能评估的相关问题。与当前最先进的磁盘体系结构相比，这些体系结构可以将办公室/工程工作负载的I/O响应时间提高几个数量级。研究的重点包括：*通过磁盘缓存磁盘(DCD)的方式最小化磁盘写入时间。这是一种使用小磁盘按顺序缓存写入的技术，就像在日志结构的文件系统中一样，然后使用日志更新较大磁盘上的文件系统。*结合使用DRAM和DCD来取代当前在RAID系统中使用的非易失性RAM缓存。*使用DRAM作为文件系统的组件，以实现快速读写。在此方案中，写入RAM的文件的日志将保存在NVRAM或磁盘上，但只有RAM访问将位于关键路径中。*升级现有文件服务器以使用多个现有磁盘模拟DCD。这些体系结构将通过模拟进行研究，以便在各种I/O工作负载下将它们与现有体系结构进行比较。还将设计新的分析模型，并将其用于建筑评估。DCD结构的实际实施将使用磁盘分区作为该部计算机上的高速缓存。性能测量将在DCD实施上执行，并用于与现有磁盘体系结构进行比较。

This research is investigating the issues related to designs and performance evaluations of several innovative disk I/O architectures. These architectures may improve the I/O response time by orders of magnitude over current state-of-the-art disk architectures for office/engineering workloads. The focus of the research includes: * Minimization of disk write times by means of disk caching disk (DCD). This is a technique of using a small disk to cache writes sequentially, as in a log-structured file system, then using the log to update the file system on the larger disks. * Using a combination of DRAM and DCD to replace non-volatile RAM caches that are currently used in RAID systems. * Using DRAM as a component of the file system to allow fast reads and writes. In this scheme, a log of files written to RAM will be kept in either NVRAM or on disk, but only the RAM access will be in the critical path. * Upgrading existing file servers to emulate DCD using multiple existing disks. These architectures will be investigated using simulation to compare them to existing architectures under a wide range of I/O workloads. New analytical models will also be devised and used in evaluation of architectures. Actual implementations of the DCD architectures will be carried out using disk partitions as caches on the computers in the department. Performance measurements will be performed on the DCD implementations and used to compare with existing disk architectures.