Unanimous: System Research Group talklet

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I’m looking forward to sharing my thoughts on consensus for the edge network with the SRG today, abstract below

Many projects in the SRG at the moment (HAT, UCN, contacts app, MirageOS for ARM, Jitsu, databox, signposts) are trying to give individuals an viable alternative to 3rd party centralised services and put them back in control of their personal data. However developing applications for the hostile edge network, with its heterogeneous hosts and networks, trust issues and poorly understood middle boxes is tricky. This is made worse by the fact that consensus algorithms are famously difficult to use, underspecified and based on decade old assumption about the internet. In this talklet, I will motivate Unanimous, a new consensus algorithm for the modern internet.

NB: this is a practice talk for EuroSys doctoral workshop next Tuesday, thus this 5 min talk will simply motivate a research direction instead of presenting a complete solution.
EDIT (17/4): these slides are now online

Raft Refloated: Do We Have Consensus?

The January edition of SIGOPS Operating Systems Review is out now and thus is the aptly named “Raft Refloated: Do We Have Consensus?”. This is my first journal paper and I’m really existed to see what the community makes of it.

Title: Raft Refloated: Do We Have Consensus?
Authors: Heidi Howard, Malte Schwarzkopf, Anil Madhavapeddy and Jon Crowcroft
Paper: acm dl, open access link
Abstract: The Paxos algorithm is famously difficult to reason about and even more so to implement, despite having been synonymous with distributed consensus for over a decade. The recently proposed Raft protocol lays claim to being a new, understandable consensus algorithm, improving on Paxos without making compromises in performance or correctness.

In this study, we repeat the Raft authors’ performance analysis. We developed a clean-slate implementation of the Raft protocol and built an event-driven simulation framework for prototyping it on experimental topologies. We propose several optimizations to the Raft protocol and demonstrate their effectiveness under contention. Finally, we empirically validate the correctness of the Raft protocol invariants and evaluate Raft’s understandability claims.

Below is the key figure of the paper, showing a side-by-side comparison of the simulation results next to the authors’ original results.

fig15-original

fig15-replicate