An interactive explainer

A handful of servers, some of which will crash, still agree on one version of the truth.

No machine is in charge in advance. Any of them can lag or crash. Even so, the cluster returns a single ordered history that every server replays the same way. The trick is not trust. It is arithmetic. Watch a leader get elected the way a jury picks a foreman. Watch a command become law only once a majority has written it down. Then take the failure dial yourself. Kill one follower and the truth holds. Kill the majority and the system would rather stall than lie.

Consensus · Raft · Leader election · Quorum

Systems · Advanced · 12 min · Jury duty for servers — an interactive explainer on ViLearn, with a simulation and a knowledge check. All explainers.

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