NVMe-oAF: Towards Adaptive NVMe-oF for IO-Intensive Workloads on HPC Cloud

Applications running inside containers or virtual machines, traditionally use TCP/IP for communication in HPC clouds and data centers. The TCP/IP path usually becomes a major performance bottleneck for applications performing NVMe-over-Fabrics (NVMe-oF) based I/O operations in disaggregated storage settings. We propose an adaptive communication channel, called NVMe-over-Adaptive-Fabric (NVMe-oAF), that applications could leverage to eliminate the high-latency and low-bandwidth incurred by remote I/O requests over TCP/IP. NVMe-oAF accelerates I/O intensive applications using locality awareness along with optimized shared memory and TCP/IP paths. The adaptiveness of the fabric stems from the ability to adaptively select shared memory or TCP channel and further applying optimizations for the chosen channel. To evaluate NVMe-oAF, we co-design Intel's SPDK library with our designs and show up to 7.1x bandwidth improvement and up to 4.2x latency reduction for various workloads over commodity TCP/IP-based Ethernet networks (e.g., 10Gbps, 25Gbps, and 100Gbps). We achieve similar (or sometimes better) performance when compared to NVMe-over-RDMA by avoiding the cumbersome management of RDMA in HPC cloud environments. Finally, we also co-design NVMe-oAF with H5bench to showcase the benefit it brings to HDF5 applications. Our evaluation indicates up to a 7x bandwidth improvement when compared with the network file system (NFS).