(Korakit Seemakhupt, UVA, presenting Wed. October 14 at 11:00 a.m. and 7:00 p.m. ET)
To guarantee data persistence, storage workloads (such as databases, key-value stores, and file systems) typically use a synchronous protocol that puts network and server stack latency on the critical path of request processing. The use of the fast and byte-addressable persistent memory (PM) has helped mitigate the storage overhead of the server stack; yet, networking is still a dominant factor in the end-to-end latency of request processing. Emerging programmable network devices can reduce network latency by moving parts of the applications’ compute into the network (e.g., caching results for read requests); however, for update requests, the client still has to stall on the server to commit the updates, persistently.
In this work, we introduce in-network data persistence that extends the data-persistence domain from servers to the network, and present PMNet, a network device (e.g., switch or NIC) with PM for persisting data in-network. PMNet logs incoming update requests and acknowledges clients directly without having them to wait on the server to commit the request. In case of a failure, the logged requests act as redo logs for the server to recover. We implement PMNet using an FPGA and evaluate its performance against PM-optimized key-value stores and a database. Our evaluation shows that PMNet can improve the throughput of update requests by 4.27x on average, and the 99th-percentile tail latency by 3.23x.
