纯用户态的网络文件系统——RUFS

针对在使用高速存储硬件时常规网络文件系统会被软件开销影响整体性能的问题，提出了利用存储性能开发套件（SPDK）搭建文件系统的方法，并在此基础上实现了一个网络文件系统RUFS的原型。该系统通过键值存储模拟文件系统的目录树结构以及对文件系统的元数据进行管理，通过SPDK存储文件的内容。另外，利用远程直接内存访问（RDMA）技术对外提供文件系统服务。RUFS相较于NFS+ext4，在4 KB随机访问上，读写吞吐性能分别提高了202.2%和738.9%，读写平均延迟分别降低了74.4%和97.2%；在4 MB顺序访问上，读写吞吐性能分别提高了153.1%和44.0%。在大部分元数据操作上，RUFS相比NFS+ext4也有显著优势，特别是文件夹创建操作，RUFS的吞吐性能提高了约5 693.8%。该系统能够充分发挥高速网络和高速存储设备的性能优势，为用户提供延时更低、吞吐性能更好的文件系统服务。

RUFS: a pure userspace network file system

The overall performance of traditional network file system is affected by software overhead when using high-speed storage device. Therefore, a method of constructing a file system using SPDK (Storage Performance Development Kit) was proposed, and a prototype of a network file system RUFS (Remote Userspace File System) was realized on this basis. In this system, the directory tree structure of file system was simulated and the metadata of file system were managed by using key-value storage, and the file contents were stored by using SPDK. Besides, RDMA (Remote Direct Memory Access) technology was used to provide file system service to clients. Compared with NFS+ext4, on 4 KB random access, RUFS had the read and write bandwidth performance increased by 202.2% in read and 738.9% respectively, and had the average read and write latency decreased by 74.4% and 97.2% respectively; on 4 MB sequential access, RUFS had the read and write bandwidth performance increased by 153.1% and 44.0% respectively. RUFS had significant advantages over NFS+ext4 on most metadata operations, especially on the operation of folder creation, RUFS had the bandwidth performance increased by about 5 693.8%. File system service with lower latency and higher bandwidth can be provided by this system via making full use of the performance advantages of the high-speed network and high-speed storage device.