NeTS:Small:Understanding the Impact of Unreliable Hardware on the Resilience of Networked Systems

网络系统一直被设计成即使在出现故障的情况下也能运行，特别是在通信链路和存储设备中。直到最近，此类系统的其他组件的故障概率都相对较低，对于大多数联网系统，可以使用以特别方式添加的最小冗余来实现所需的弹性级别。未来几年，两个相反的趋势可能会使实现弹性的任务变得更加困难：(A)越来越多的硬件故障概率：随着向更精细的纳米级制造的转变，芯片越来越容易受到外部噪声造成的软错误的影响，并且越来越有可能因疲劳而过早失败；(B)更高的弹性要求：随着关键服务继续迁移到云，服务提供商被迫签订更严格的服务级别协议(SLA)，包括更高的可靠性、更高的可用性和更严格的服务时间保证。上述组合可能会极大地增加现有方法的开销，以实现预期的复原力水平。智力优势：该项目的第一个成果将是网络系统弹性的整体路线图。这份弹性路线图将采用纳米级芯片芯片的路线图(芯片成本、功能、性能、功率和弹性方面的趋势，可以在芯片级别实现)，并试图现实地预测当前使用的网络和系统技术的未来成本，以实现所需的弹性水平。该项目的第二个成果是开发在面对越来越多的硬件故障时能够优雅地扩展的弹性方法。这种技术将使用新颖的分区冗余策略，在硬件和软件层的不同级别实现可靠性。更广泛的影响。复原力路线图将提供对复原力趋势的前所未有的了解，以及对挑战和机遇的独特而现实的评估。这将对硬件和网络社区的研究产生重大影响。系统地设计可扩展的复原力方法将导致更高的复原力水平、更低的成本-资本(设备)以及经常性(特别是能源)，和/或更高的性能水平。由于联网系统现在构成了我们最重要的基础设施之一，并消耗了越来越多的资源，因此拟议项目可能会为社会带来巨大的实用收益。这个项目将利用硬件架构和联网系统这两个不同的学科，并涉及详细的案例研究和全新理论和技术的开发，因此将为这些领域的学生和在职专业人员提供独特的教育和培训机会。预算影响报表：本段中的项目数字是指我们最初建议的图9和第3.2节(拟议的研究任务和计划)中的项目数字。我们将承担第一项(及其所有分项)中提出的所有任务和子任务。在项目2中，我们将着手制定一个总框架，以审议所有基本的冗余计划和部署这些计划的替代方法(分项2.1)。我们还将描述相关的权衡(子项-2.2)和现实约束的后果(子项-2.3)。但是，我们将继续开发原型工具(如分项-2.4所述)，以显示我们方法的益处并进行案例研究(在分项-3所述)。最后，我们将按照项目-3的最初提议进行个案研究。

Networked systems have always been designed to operate even in the presence of failures, especially in communication links and storage. Until recently other components of such systems had relatively low probabilities of failures and for most networked systems, desired levels of resilience could be achieved using minimal redundancy added in an ad hoc manner. Two opposing trends are likely to make the task of achieving resilience significantly more difficult in the coming years: (a) increasing hardware failure probabilities: with the move towards finer nano-scale fabrication, chips are increasingly vulnerable to soft errors caused by external noise and are increasingly likely to fail early due to fatigue; (b) higher resilience requirements: as critical services continue to migrate to clouds, service providers are compelled into more stringent service-level agreements (SLAs), including higher reliability, higher availability, and tighter guarantees on service times. The above combination can dramatically increase the overhead of existing approaches for achieving desired levels of resilience. Intellectual merit: The first outcome of this project will be a holistic roadmap for resilience of networked systems. This resilience roadmap will take the roadmaps from the nano-scale CMOS (trends in chip cost, functionality, performance, power, and resilience that can be attained at chip level) and attempt to realistically project the future cost of currently-used networking and systems techniques for achieving desired level of resilience. The second outcome of this project is to develop resilience methods that scale gracefully in the face of increasing hardware failures. Such techniques will use novel partitioned redundancy strategies that achieve reliability at different levels across hardware and software layers. Broader Impacts. The resilience roadmap will provide unprecedented understanding of the trends in resilience and a uniquely realistic assessment of challenges and opportunities. This will significantly influence the research in the hardware as well as networking communities. A systematic design of scalable resilience methods will lead to significantly higher levels of resilience, lower costs - capital (equipment) as well recurring (especially, energy), and/or higher levels of performance. The utilitarian gains to society by the proposed project are likely to be substantial, since networked systems now constitute one of our most critical infrastructures and consume an increasingly large proportion of our resources.This project will draw upon two different disciplines, hardware architecture and networked systems, and involve detailed case studies and development of completely new theory and techniques, and will therefore provide unique educational and training opportunities for students and working professionals in these fields.Budget Impact Statement: The item numbers in this paragraph refer to those in Figure 9 and Section 3.2 (entitled 'Proposed Research Tasks and Plan') of our original proposal. We will undertake all tasks and sub-tasks proposed in item-1 (and all its sub-items). In item-2, we will undertake the development of a general framework to consider all basic redundancy schemes and alternative ways of deploying them (sub-item-2.1). We will also characterize the associated tradeoffs (sub-item-2.2) and the consequences of realistic constraints (sub-item-2.3). However, we will pursue the development of prototype tools (as outlined in sub-item-2.4), to the extent necessary to demonstrate the benefits of our approach and to conduct case studies (described in item-3). Finally, we will undertake the case studies as originally proposed in item-3.