Evaluating File System Reliability on Solid State Drives
Evaluating File System Reliability on Solid State Drives
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发表时间：
2019
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通讯作者：
Shehbaz Jaffer;Stathis Maneas;Andy A. Hwang;Bianca Schroeder
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作者：
Shehbaz Jaffer;Stathis Maneas;Andy A. Hwang;Bianca Schroeder
随着固态硬盘 (SSD) 越来越多地取代硬盘驱动器，存储系统的可靠性取决于 SSD 的故障模式以及顶层文件系统处理这些故障模式的能力。虽然关于 IRON 文件系统的经典论文对当时常见的三种文件系统的故障策略进行了全面研究，但我们认为 13 年后，是时候重新审视 SSD 文件系统的可靠性及其可靠性特征了，基于现代文件系统，结合了日志记录、写时复制和日志结构方法，并针对闪存进行了优化。本文提出了详细的研究，涵盖 ext4、Btrfs 和 F2FS，并涵盖了许多不同的 SSD 错误模式。我们开发了自己的故障注入框架并探索了一千多个错误案例。我们的结果表明，其中 16% 的情况会导致文件系统无法由系统检查程序安装甚至修复。我们还确定了可能导致此类故障的关键文件系统元数据结构，最后，我们为部署在 SSD 上的文件系统推荐了一些设计指南。
As solid state drives (SSDs) are increasingly replacing hard disk drives, the reliability of storage systems depends on the failure modes of SSDs and the ability of the file system layered on top to handle these failure modes. While the classical paper on IRON File Systems provides a thorough study of the failure policies of three file systems common at the time, we argue that 13 years later it is time to revisit file system reliability with SSDs and their reliability characteristics in mind, based on modern file systems that incorporate journaling, copy-on-write and log-structured approaches, and are optimized for flash. This paper presents a detailed study, spanning ext4, Btrfs and F2FS, and covering a number of different SSD error modes. We develop our own fault injection framework and explore over a thousand error cases. Our results indicate that 16% of these cases result in a file system that cannot be mounted or even repaired by its system checker. We also identify the key file system metadata structures that can cause such failures and finally, we recommend some design guidelines for file systems that are deployed on top of SSDs.