CNS Core: Medium: Collaborative Research: Cross Layer File Systems

计算机硬件设计人员正在开发用于永久存储用户数据的新技术，如非易失性存储器（NVM）和固态磁盘（SSD）。与十年前普遍使用的存储技术相比，这些技术提供了前所未有的性能，但每兆字节存储的成本也要高得多。这项工作使用软件来弥合这一差距：构建可以无缝跨越多种存储技术的文件存储系统，从NVM到SSD再到传统磁盘存储，以低成本和高性能可靠地存储用户数据。一个关键的创新是改变应用程序和操作系统之间的接口，以简化文件系统更新。应用程序请求内核允许在每个应用程序NVM中记录对文件系统的更改。这些更改可以在性能接近NVM硬件限制的情况下应用，每次更新通常低于一微秒。在后台，内核将这些更改复制回自己的数据区域，提供所有应用程序都在同一存储系统上工作的假象。然后，内核将数据复制到SSD和磁盘，以便为NVM的其他更新腾出空间。由于这些新技术带来的优势，工业界正急于部署这些新技术，但要将这些优势带给真正的用户，还需要新的软件技术。由于桌面和云计算系统是全球数十亿人使用的所有类型计算的默认平台，因此有可能带来广泛的好处。此外，计算机科学教学必须适应这些新技术的挑战和解决方案，使学生在这种新环境中茁壮成长。建议的讲座和专题材料将使学生为多层存储和文件系统的未来做好准备。生成的主要数据类型将是软件工件和这些软件工件的度量。在项目期间，软件源代码和数据测量将使用行业标准的版本控制系统进行存储，并备份在德克萨斯大学奥斯汀分校计算机科学系大楼不同区域的多个服务器上。发表后，源代码和数据测量的副本将与所有已发表论文的副本一起移动到https://www.cs.utexas.edu/~simon/strata/的永久存储库中，该存储库将在项目完成后至少保留十年。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

Computer hardware designers are developing new technologies for permanent storage of user data, such as non-volatile memories (NVM) and solid-state disks (SSD). Relative to the storage technologies commonly used just a decade ago, these offer unprecedented performance, but at a cost that is also much higher per megabyte of storage. This work uses software to bridge that gap: to build file storage systems that can seamlessly span multiple types of storage technology, from NVM to SSD to traditional disk storage, to reliably store user data at low cost and high performance.A key innovation is to change the interface between applications and the operating system to streamline file system updates. Applications ask the kernel for permission to log changes to the file system in per-application NVM. These changes can be applied with performance close to the hardware limits of NVM, often under a microsecond per update. In the background, the kernel copies these changes back to its own data region, providing the illusion that all applications are working on the same storage system. The kernel then copies the data to SSD and disk to make room for additional updates to NVM.Industry is rushing to deploy these new technologies because of the advantages they bring, but new software techniques are needed to bring those advantages to real users. As desktops and cloud computing systems are the default platform for all types of computing used by billions of people worldwide, there is the potential for widespread benefit. In addition, computer science instruction must adapt to address the challenges and solutions to these new technologies, to enable students to thrive in this new environment. Proposed lecture and project materials will prepare students for this multi-layer storage and file system future.The primary type of data to be produced will be software artifacts and measurements of these software artifacts. During the project, software source code and data measurements will be stored using an industry-standard version control system and backed up on multiple servers in different areas of the University of Texas Austin computer science department building. After publication, copies of the source code and data measurements will be moved, along with copies of all published papers, to a permanent repository at https://www.cs.utexas.edu/~simon/strata/ which will remain in place for at least ten years after completion of the project.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.