Moneta: A High-Performance Storage Array Architecture for Next-Generation, Non-volatile Memories

Emerging non-volatile memory technologies such as phase change memory (PCM) promise to increase storage system performance by a wide margin relative to both conventional disks and flash-based SSDs. Realizing this potential will require significant changes to the way systems interact with storage devices as well as a rethinking of the storage devices themselves. This paper describes the architecture of a prototype PCIe-attached storage array built from emulated PCM storage called Moneta. Moneta provides a carefully designed hardware/software interface that makes issuing and completing accesses atomic. The atomic management interface, combined with hardware scheduling optimizations, and an optimized storage stack increases performance for small, random accesses by 18x and reduces software overheads by 60%. Moneta array sustain 2.8~GB/s for sequential transfers and 541K random 4~KB~IO operations per second (8x higher than a state-of-the-art flash-based SSD). Moneta can perform a 512-byte write in 9~us (5.6x faster than the SSD). Moneta provides a harmonic mean speedup of 2.1x and a maximum speed up of 9x across a range of file system, paging, and database workloads. We also explore trade-offs in Moneta's architecture between performance, power, memory organization, and memory latency.