XPS: FULL: FP: Collaborative Research: Synchrony-aware Primitives for Building Highly Auditable, Highly Scalable, Highly Available Distributed Systems

XPS：完整：FP：协作研究：用于构建高度可审计、高度可扩展、高度可用的分布式系统的同步感知原语

• 批准号: 1533802
• 负责人: Sandeep Kulkarni
• 金额: $ 35万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1533802&HistoricalAwards=false
• 关键词: XPS; FULL; FP; Collaborative; Research

Auditability is a key property for developing highly scalable and highly available distributed systems, as it enables identifying performance bottlenecks, dependencies among events, and latent concurrency bugs. In turn, for the auditability of a system, time is a key concept. However, there is a gap between the theory and the practice of distributed systems in terms of the use of time. The theory of distributed systems shuns the notion of time and considers asynchronous systems whose event ordering is captured by logical clocks. The practical distributed systems employ NTP synchronized clocks to capture time but tend to use ad hoc methods. This project bridges this gap and provides synchrony-aware system primitives that support building highly auditable, highly scalable, and highly available distributed systems. The project has applications to cloud computing, distributed NewSQL databases, and globally distributed web services. The project enables other broader impacts through enhancing scientific/technological understanding via organizing academic workshops, outreaching to K-12 students, recruitment of minority groups, and distributing tools and software to the community.To enable highly auditable systems, the project investigates lightweight and efficient designs for an augmented time (AT) primitive. AT combines the theoretical underpinnings of causality and the practicality of physical clocks by identifying how logical/vector clocks can be improved and tuned based on the availability of NTP synchronization. The principle guiding AT design will be "uncertainty resilience". These AT clocks enable highly auditable systems since they can efficiently provide global consistent-state snapshots without needing to wait out clock synchronization uncertainties and without requiring prior coordination. Leveraging on these auditability primitives, the project builds support for scalable and available systems. To enable highly scalable systems, the project investigates design of synchrony-aware coordination primitives, such as barrier synchronization, mutual exclusion, leader election, and causally and totally ordered communication support. The principle guiding the design of the synchrony-aware coordination primitives is "silent consent". These primitives improve performance and efficiency over their asynchronous system counterparts by trading timing information gathered from AT clocks and avoiding explicit communication needed for coordination. Finally, the project will leverage the auditability support provided by AT and will investigate the design of a monitor component that detects and corrects distributed system state corruptions. The principle guiding the design of the monitor component is "centralized oversight and override".

可审计性是开发高度可伸缩和高度可用的分布式系统的关键属性，因为它可以识别性能瓶颈，事件之间的依赖关系和潜在的并发错误。 反过来，对于系统的可扩展性，时间是一个关键概念。 然而，分布式系统的理论和实践在时间利用方面存在差距。分布式系统的理论回避了时间的概念，并考虑了异步系统，其事件顺序由逻辑时钟捕获。实际的分布式系统采用NTP同步时钟来捕获时间，但倾向于使用ad hoc方法。该项目弥补了这一差距，并提供了同步感知系统原语，支持构建高度可审计、高度可伸缩和高度可用的分布式系统。该项目应用于云计算、分布式NewSQL数据库和全球分布式Web服务。该项目通过组织学术研讨会、向K-12学生推广、招募少数群体以及向社区分发工具和软件来增强科学/技术理解，从而实现其他更广泛的影响。为了实现高度可审计的系统，该项目研究了增强时间（AT）原语的轻量级和高效设计。AT结合了因果关系的理论基础和物理时钟的实用性，确定了如何根据NTP同步的可用性来改进和调整逻辑/矢量时钟。AT设计的指导原则将是“不确定性弹性”。这些AT时钟使系统具有高度可审计性，因为它们可以有效地提供全局一致状态快照，而无需等待时钟同步不确定性，也无需事先协调。 利用这些可扩展性原语，该项目构建了对可扩展和可用系统的支持。为了实现高度可扩展的系统，该项目研究了同步感知协调原语的设计，如障碍同步，互斥，领导者选举，因果关系和完全有序的通信支持。设计同步感知协调原语的指导原则是“沉默同意”。这些原语通过交换从AT时钟收集的定时信息并避免协调所需的显式通信，来提高异步系统的性能和效率。最后，该项目将利用AT提供的可扩展性支持，并将研究检测和纠正分布式系统状态损坏的监视器组件的设计。设计监测器组件的指导原则是“集中监督和控制”。