The increasing demand for SSDs coupled with scaling difficulties has left manufacturers scrambling for newer SSD interfaces which promise better performance and durability. While these interfaces reduce the rigidity of traditional abstractions, they require application or system-level changes that can impact the stability, security, and portability of systems. To make matters worse, such changes are rendered futile with the introduction of next-generation interfaces. It is therefore no surprise that such interfaces have seen limited adoption, leaving behind a graveyard of experimental interfaces ranging from open-channel SSDs to stream SSDs. Our solution, Valet, leverages userspace shim layers to add placement hints for application data, delivering up to 2-4x write throughput over filesystems and comparable or better performance than application-specific solutions, with up to 6x lower tail latency. Valet generates dynamic placement hints, remapping application data to modern SSDs with zero modifications to the application, the filesystem, or the kernel. We demonstrate performance, efficiency, and multi-tenancy benefits of Valet across a set of widely-used applications: RocksDB, MongoDB, and CacheLib, presenting a solution that combines the performance of application-specific solutions with wide applicability to log-structured data-intensive applications.

翻译：随着对固态硬盘需求的不断增长以及制造工艺的微缩挑战，制造商正竞相推出承诺更高性能和耐久性的新型固态硬盘接口。尽管这些接口降低了传统抽象层的僵化性，但它们需要应用或系统层面的改动，这可能影响系统的稳定性、安全性和可移植性。更严峻的是，当新一代接口问世时，此类改动往往变得徒劳无功。因此，这类接口的采用范围有限，留下了从开放通道固态硬盘到流式固态硬盘等各类实验性接口的‘技术坟场’。我们提出的解决方案Valet，通过用户空间适配层为应用数据添加布局提示，相比传统文件系统实现了高达2-4倍的写入吞吐量提升，与专用应用解决方案相比也展现出相当或更优的性能，尾部延迟最高可降低6倍。Valet能动态生成布局提示，将应用数据重新映射至现代固态硬盘，且无需对应用程序、文件系统或内核进行任何修改。我们通过一组广泛使用的应用——RocksDB、MongoDB和CacheLib——展示了Valet在性能、效率和多租户方面的优势，提出了一种既能保持专用解决方案性能，又能广泛适用于日志结构数据密集型应用的综合性方案。