Emerging fast, non-volatile memories will enable systems with large amounts of non-volatile main memory (NVMM) attached to the CPU memory bus, bringing the possibility of dramatic performance gains for IO-intensive applications. This paper analyzes the impact of state-of-the-art NVMM storage systems on some of these applications and explores how those applications can best leverage the performance that NVMMs offer. Our analysis leads to several conclusions about how systems and applications should adapt to NVMMs. We propose FiLe Emulation with DAX (FLEX), a technique for moving file operations into user space, and show it and other simple changes can dramatically improve application performance. We examine the scalability of NVMM file systems in light of the rising core counts and pronounced NUMA effects in modern systems, and propose changes to Linux's virtual file system (VFS) to improve scalability. We also show that adding NUMA-aware interfaces to an NVMM file system can significantly improve performance.

Emerging fast, persistent memories will enable systems that combine conventional DRAM with large amounts of non-volatile main memory (NVMM) and provide huge increases in storage performance. Fully realizing this potential requires fundamental changes in how system software manages, protects, and provides access to data that resides in NVMM. We address these needs by describing an NVMM-optimized file system called NOVA-Fortis that is both fast and resilient in the face of corruption due to media errors and software bugs. We identify and propose solutions for the unique challenges in adding fault tolerance to an NVMM file system, adapt state-of-the-art reliability techniques to an NVMM file system, and quantify the performance and storage overheads of these techniques. We find that NOVA-Fortis' reliability features consume 14.8% of the storage for redundancy and reduce application-level performance by between 2% and 38% compared to the same file system with the features removed. NOVA-Fortis outperforms DAX-aware file systems without reliability features by 1.5x on average. It outperforms reliable, block-based file systems running on NVMM by 3x on average.