Building a distributed key-value store with FPGA-based microservers

Energy efficiency is one of the major challenges in datacenters, and a promising way to tackle it are microservers. These scaled down machines with smaller CPUs, less peripherals and tighter integration improve energy efficiency, but often at the expense of lower performance. In this work we explore the tailoring of standard software components to specialized hardware as a way to get the energy efficiency of microservers without compromising performance. Our specialized microserver implements memcached, a common component in many web stacks, on a cluster of FPGAs. The design explores aspects such as pipelining techniques, tight integration with the network stack, dealing with the memory bottleneck, and shows how to build a complete system out of individual microservers. To our knowledge this is the first stand-alone FPGA-based solution that can be used as a drop-in replacement for the software version. Beyond the per-node performance, in this demo we focus on the replication and the integration aspects of our system. We run a common benchmark on a PostgreSQL database with a two-node deployment of FPGAs acting as a cache for query results.