Every distributed system faces the same fundamental problem: how do multiple nodes agree on the state of the world? Consensus algorithms solve this, but choosing the right one for your specific workload is the difference between a system that scales effortlessly and one that collapses under pressure.
Raft and Paxos dominate the literature, but production reveals nuances papers gloss over. Network partitions don't behave like textbook examples. Leader elections under real-world latency distributions create availability gaps theoretical models undercount.
We've found that consensus choice should be driven by three factors: consistency requirements, geographic distribution, and acceptable write latency.
"The best consensus algorithm is the one your operations team can debug at 3 AM during a multi-region partition."
For most enterprise workloads, start with Raft-based systems (etcd, CockroachDB) for operational simplicity. Evaluate EPaxos or Flexible Paxos variants only when you have empirical evidence that leader-based consensus creates a bottleneck.