A Highly Non-Volatile Memory Scalable and Efficient File System

With the rapid development of fast and byte-addressable non-volatile memories (NVMs), hybrid NVM/DRAM storage systems become promising for computer systems. Existing NVM file systems have already been optimized around the NVM properties. However, they inherit some design choices of block-oriented storage devices that lead to scalability bottlenecks and data copy overhead for ensuring data consistency. In this paper, we present noseFS, a highly non-volatile memory scalable and efficient File System. It is designed to achieve high performance through a bundle of novel techniques: (1) a scalable lightweight naming integrating VFS with the underlying file system namespace, (2) a fine-grained byte-unit file index tree avoiding redundant copy overhead introduced by Copy-On-Write, (3) a lightweight journaling providing atomicity and scalability on many-core platforms, and (4) a lightweight atomic-mmap providing strong consistency guarantee with low overhead by tracking dirty pages. Experimental results show that noseFS performs much better than the state-of-the-art file systems with equally strong data consistency guarantees, and achieves near-linear scalability on a 40-core machine.