The IO performance of storage devices has accelerated from hundreds of IOPS five years ago, to hundreds of thousands of IOPS today, and tens of millions of IOPS projected in five years. This sharp evolution is primarily due to the introduction of NAND-flash devices and their data parallel design. In this work, we demonstrate that the block layer within the operating system, originally designed to handle thousands of IOPS, has become a bottleneck to overall storage system performance, specially on the high NUMA-factor processors systems that are becoming commonplace. We describe the design of a next generation block layer that is capable of handling tens of millions of IOPS on a multi-core system equipped with a single storage device. Our experiments show that our design scales graciously with the number of cores, even on NUMA systems with multiple sockets.

SIGMOD has offered, since 2008, to verify the experiments published in the papers accepted at the conference. This year, we have been in charge of reproducing the experiments provided by the authors (repeatability), and exploring changes to experiment parameters (workability). In this paper, we assess the SIGMOD repeatability process in terms of participation, review process and results. While the participation is stable in terms of number of submissions, we find this year a sharp contrast between the high participation from Asian authors and the low participation from American authors. We also find that most experiments are distributed as Linux packages accompanied by instructions on how to setup and run the experiments. We are still far from the vision of executable papers.

We introduce ZNSwap , a novel swap subsystem optimized for the recent Zoned Namespace (ZNS) SSDs. ZNSwap leverages ZNS’s explicit control over data management on the drive and introduces a space-efficient host-side Garbage Collector (GC) for swap storage co-designed with the OS swap logic. ZNSwap enables cross-layer optimizations, such as direct access to the in-kernel swap usage statistics by the GC to enable fine-grain swap storage management, and correct accounting of the GC bandwidth usage in the OS resource isolation mechanisms to improve performance isolation in multi-tenant environments. We evaluate ZNSwap using standard Linux swap benchmarks and two production key-value stores. ZNSwap shows significant performance benefits over the Linux swap on traditional SSDs, such as stable throughput for different memory access patterns, and 10 × lower 99th percentile latency and 5 × higher throughput for memcached key-value store under realistic usage scenarios.