CSR: Small: System Support for SSD-Backed Recoverable Network Applications

网络系统庞大的硬件规模、错综复杂的软件复杂性以及错综复杂的外部交互共同破坏了可靠性：规模增加了故障的频率，而互联则通过将局部灾难转变为全球灾难来加剧其后果。该项目将在两个基础上为可恢复的网络应用建立新的系统支持。在单个计算机中，如果永久存储上的应用程序状态始终保持一致，则可以极大地简化快速、简单的应用程序恢复。在网络系统中，如果应用程序组件在向其他应用程序组件发出任何输出之前提交本地状态，则可以更好地支持容错和全局一致性。现在正是这一努力的好时机，因为新兴的基于闪存的固态磁盘(SSD)有望大幅降低所需的持久状态管理成本。研究将沿着三个方面进行：首先，该项目将设计和实现一种新的操作系统机制(快速同步日志记录，无需双重写入)，用于SSD上的原子、同步I/O故障。其次，为了广泛的适用性，本项目将为程序员提供熟悉的POSIX接口的简单扩展。第三，为了实现效率和公平，研究将开发一种新的I/O资源管理器，将经典的公平排队调度与面向SSD的预期I/O相结合。在该项目中开发的快速、简单的故障恢复机制将为对当今数字经济和社会至关重要的广泛网络应用程序提供高可靠性。该项目还将涉及行业合作、课程改进和学生培训。

The massive hardware scale, labyrinthine software complexity, and tangled external interactions of networked systems conspire to undermine reliability: Scale increases the frequency of failures while interconnectedness exacerbates their consequences by turning local mishaps into global disasters. This project will establish new system support toward recoverable network applications on two foundations. In an individual machine, fast, simple application recovery can be greatly eased if the application state on the persistent storage is kept always consistent. Over a networked system, the fault-tolerance and global consistency can be better supported and reasoned if application components commit local state before emitting any output to others. The time is right for this effort, because emerging Flash-based solid-state disks (SSDs) promise to dramatically reduce the cost of required persistent state management. Research will proceed along three fronts: First, the project will design and implement a new operating system mechanism (fast synchronous logging without double writes) for failure-atomic, synchronous I/O on SSDs. Second, for broad applicability, this project will present the programmers with simple extensions of familiar POSIX interfaces. Third, to achieve efficiency and fairness, research will develop a new I/O resource manager that combines the classic fair queuing scheduling with SSD-oriented anticipatory I/O. Fast, simple failure recovery mechanisms developed in this project will enable high reliability for a broad range of networked applications that are critical to today's digital economy and society. This project will also involve industry collaboration, curriculum enhancement, and student training.