Carrying Complexity, Delivering Agility

Details the application of formal methods to replication and failover protocols, including logless reconfiguration and multi-shard transaction protocols, using TLA+ to model core logic and verify invariants like terms blocking stale primaries, monotonic versions preventing forks, majority votes stopping minority splits, and the oplog-commit rule ensuring durability. It also highlights the use of automated model-based techniques for testing the WiredTiger storage interface and assessing concurrency maximization within isolation levels.