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

网络系统一直被设计为即使在存在故障的情况下也能运行，特别是在通信链路和存储方面。直到最近，此类系统的其他组件的故障概率相对较低，并且对于大多数网络系统，可以使用以特别方式添加的最小冗余来实现所需的弹性水平。在未来几年中，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)硬件故障概率的增加：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引起的软错误的影响，并且越来越容易因疲劳而提前失效；(b)更高的弹性要求：随着关键服务不断迁移到云，服务提供商被迫采用更严格的服务水平协议（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。上述组合可以显著增加现有方法的开销，以实现所需的弹性水平。智力价值：这个项目的第一个成果将是网络系统弹性的整体路线图。该弹性路线图将采用纳米级CMOS的路线图（芯片成本、功能、性能、功耗和弹性的趋势，可以在芯片级别上获得），并尝试实际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弹性方法，这些方法可以在硬件故障不断增加的情况下优雅地扩展。这些技术将使用新的分区冗余策略，在硬件和软件层的不同级别上实现可靠性。更广泛的影响。复原力路线图将对复原力趋势提供前所未有的理解，并对挑战和机遇进行独特的现实评估。这将对硬件和网络社区的研究产生重大影响。可扩展弹性方法的系统设计将显著提高弹性水平，降低成本-资本（设备）以及循环（特别是能源），和/或更高的性能水平。由于网络系统现在构成了我们最关键的基础设施之一，并且消耗了我们越来越多的资源，因此拟议中的项目对社会的实用效益可能是巨大的。该项目将涉及硬件架构和网络系统两个不同的学科，并涉及详细的案例研究和全新理论和技术的发展，因此将为这些领域的学生和工作专业人员提供独特的教育和培训机会。预算影响说明：本段的项目编号参考图9和原始提案第3.2节（题为“建议的研究任务和计划”）中的项目编号。我们将承担第1项（及其所有分项）中提出的所有任务和子任务。在项目2中，我们将负责制定一个总体框架，以考虑所有基本的冗余方案和部署这些方案的备选办法（分项2.1）。我们还将描述相关的权衡（分项-2.2）和现实限制的后果（分项-2.3）。然而，我们将继续开发原型工具（如子项-2.4所述），以证明我们的方法的好处并进行案例研究（如子项-3所述）。最后，我们将进行项目3中最初提议的个案研究。

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.