CNS Core: Medium: The Synchronous Data Center

大多数主要的网络服务--如亚马逊、谷歌或Facebook--都部署了庞大的数据中心，每个数据中心可以容纳数十万台计算机。如今，这些数据中心几乎都是使用异步设计建造的，很少或根本没有假设两台计算机可能需要多长时间通信，或者一台计算机究竟何时能够完成给定的任务。从分布式计算一开始，“异步设计”就一直是标准；它是教科书中教授的，很少有人质疑。然而，设计并不像乍看起来那么简单：在实践中，它经常导致低效率、不可预测的时间和许多其他严重的问题。这个项目提出了一个彻底的新解决方案--同步网络--从本质上消除了这些问题。从高层次上讲，这种方法涉及创建详细的编排，描述每台计算机应该做什么以及什么时候做。虽然同步设计可能更复杂，但它们也带来了相当大的潜在好处，包括更高的效率、更好的可预测性和对新类型服务的支持。此外，它们还可以潜在地回避异步设计中的一些最困难的问题。该项目将为这一新模型开发管理体系结构和必要的算法等组件，并通过网络试验台和模拟来探索其性能。该项目正在利用来自网络物理系统的见解，这些系统几十年来一直使用同步设计，尽管规模小得多，环境也非常不同。它正在开发1)一个新的、完全同步的计算平台的原型；2)新的、可扩展的协调机制和调度技术；以及3)一套用于应用程序的同步构建块。该项目正在使用网络搜索作为一个案例研究，以展示同步方法的端到端好处。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Most major web services - such as Amazon, Google, or Facebook - employ massive data centers that can each contain hundreds of thousands of computers. Today, these data centers are almost always built using an asynchronous design, with few or no assumptions about how long it might take for two computers to communicate, or when exactly a computer might be able to complete a given task. The 'asynchronous design' has been the standard since the very beginning of distributed computing; it is the one that is taught in textbooks, and it is rarely questioned. However, the design is not as simple as it may at first appear: in practice it often leads to low efficiency, unpredictable timing, and many other serious problems. This project proposes a radical new solution--synchronous networks-- that intrinsically eliminate these problems. At a high level, this approach involves creating a detailed choreography that describes what each computer should do and when. While synchronous designs can be more complex, they also come with considerable potential benefits, including higher efficiency, better predictability, and support for new kinds of services. In addition, they can potentially sidestep some of the most difficult problems with asynchronous designs. This project will develop the management architecture and necessary algorithms and other components for this new model and explore its performance in a network testbed and through simulation. The project is leveraging insights from cyber-physical systems, which have been using synchronous designs for decades, albeit at much smaller scales and in a very different environment. It is developing 1) a prototype of a new, fully synchronous computing platform; 2) new, scalable coordination mechanisms and scheduling techniques; and 3) a set of synchronous building blocks for applications. The project is using web search as a case study to demonstrate the end-to-end benefits of the synchronous approach.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.