USENIX ATC '19: 2019 USENIX Annual Technical Conference

New non-volatile memory technologies offer unprecedented performance levels for persistent storage. However, to exploit their full potential, a deeper performance characterization of such devices is required. In this paper, we analyze a NVM-based block device -- the Intel Optane SSD -- and formalize an "unwritten contract'' of the Optane SSD. We show that violating this contract can result in 11x worse read latency and limited throughput (only 20% of peak bandwidth) regardless of parallelism. We present that this contract is relevant to features of 3D XPoint memory and Intel Optane SSD's controller/interconnect design. Finally, we discuss the implications of the contract.