Design and evaluation of a user-level file system for fast storage devices

Lately, fast storage devices are rapidly increasing in social network services, cloud platforms, etc. Unfortunately, the traditional Linux I/O stack is designed to maximize performance on disk-based storage. Emerging byte-addressable and low-latency non-volatile memory technologies (e.g., phase-change memories, MRAMs, and the memristor) provide very different characteristics, so the disk-based I/O stack cannot lead to high performance. This paper presents a high performance I/O stack for the fast storage devices. Our scheme is to remove the concept of block and to simplify the whole I/O path and software stack, which results in only two layers that are the byte-capable interface and the byte-aware file system called BAFS. We aim to minimize I/O latency and maximize bandwidth by eliminating the unnecessary layers and supporting byte-addressable I/O without requiring changes to applications. We have implemented a prototype and evaluated its performance with multiple benchmarks. The experimental results show that our I/O stack achieves 6.2 times on average and up to 17.5 times performance gains compared to the existing Linux I/O stack.