CSR: Small: Collaborative Research: Improving Latency in Geo-Replicated Storage by Relaxing Consistency Requirements

近年来，云服务的普及程度大幅增长。分布式存储系统是云计算革命的关键组成部分。分布式存储系统被设计成在延迟、数据一致性和可靠性之间实现适当的折衷。该项目致力于开发新的一致性模型，考虑到应用程序的特点和混合故障模型。最终目标是提高我们对分布式存储系统中一致性、延迟和可靠性之间的权衡的理解。该项目包括两个协同的重点。首先，该项目探索了考虑基于图的应用程序特征的一致性模型。例如，社交和信任图为许多应用程序的用户关系和交互建模。第一个重点是探索应用程序可接受的基于图的一致性模型，同时改善客户端操作的延迟。第二，现有的存储系统通常仅容忍良性故障，或者容忍具有高开销的最坏情况的故障。该项目考虑了非共谋故障以及拜占庭故障，并研究了通过放松先前系统所施加的一些要求来减少开销的方法。建议的研究，预计将提高分布式存储系统中的应用程序特性和不同类型的故障的一致性延迟权衡的影响的理解。容忍更严重的故障可能会成为未来的关键基于Web的服务和应用程序的重要。此外，随着社交和信任网络的巨大增长，提高其性能的机制也引起了人们的兴趣。该项目通过开发新的一致性模型来帮助实现这些改进。此外，该项目还为本科生和研究生以及博士后研究人员提供研究机会。项目数据将在项目完成后保留至少两年，并存储在本地计算机和在线共享存储器中。该项目产生的数据、出版物和软件的存储库的URL是https://sites.google.com/site/nsfgeoconsistency/.This奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Recent years have seen a tremendous growth in the popularity of cloud services. Distributed storage systems are a key component of the cloud computing revolution. Distributed storage systems are designed to achieve a suitable tradeoff between latency, data consistency and dependability. This project addresses development of new consistency models that take into account application characteristics and hybrid fault models. The ultimate goal is to improve our understanding of the trade-offs between consistency, latency, and dependability in distributed storage systems. The project includes two synergistic thrusts. First, the project explores consistency models that consider graph-based application characteristics. For example, social and trust graphs model user relation and interaction for many applications. The first thrust explores graph-based consistency models that are acceptable for the applications, and yet improve latency of client operations. Second, prior storage systems typically either only tolerate benign failures, or tolerate worst-case faults with high overhead. This project considers non-colluding faults as well as Byzantine faults, and investigates approaches to reduce overhead by relaxing some of the requirements imposed by prior systems. Proposed research is expected to improve the understanding of the impact of application characteristics and different types of faults on consistency-latency trade-off in distributed storage systems. Tolerance of more severe faults is likely to become important for future critical web-based services and applications. Additionally, with the tremendous growth in social and trust networks, mechanisms to improve their performance are of interest. This project helps achieve such improvements through the development of new consistency models. Additionally, the project provides research opportunities to undergraduate and graduate students, and a post-doctoral researcher.The data from the project is to be retained for at least two years after the completion of this project, and stored in local computers and online shared storage. The URL for the repository of the data, publications and software resulting from the project is https://sites.google.com/site/nsfgeoconsistency/.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.