  High-performance clusters and datacenters pose increasingly demanding
requirements on storage systems. If these systems do not operate at scale,
applications are doomed to become I/O bound and waste compute cycles. To
accelerate the data path to remote storage nodes, remote direct memory access
(RDMA) has been embraced by storage systems to let data flow from the network
to storage targets, reducing overall latency and CPU utilization. Yet, this
approach still involves CPUs on the data path to enforce storage policies such
as authentication, replication, and erasure coding. We show how storage
policies can be offloaded to fully programmable SmartNICs, without involving
host CPUs. By using PsPIN, an open-hardware SmartNIC, we show latency
improvements for writes (up to 2x), data replication (up to 2x), and erasure
coding (up to 2x), when compared to respective CPU- and RDMA-based
alternatives.
