When working with distributed systems, it’s easy to confuse Total Order Broadcast (TOB) and Linearizability. After all, both seem to talk about order. However each serve different purposes and operate at different layers of a system’s design. Let's unpack! If every replica delivers the same messages…
Modern distributed systems are built from many moving parts - databases, services, queues, caches, and schedulers - all operating concurrently and often out of sync. The only reason this doesn’t collapse into chaos is coordination. Coordination is how independent components stay aligned - who leads, who follows, who owns…
Consensus is what turns a collection of replicas into a single, coherent truth. But it’s also what slows that truth down. The scope of Consensus must be chosen carefully, because it comes with a cost. Without restraint, no system can remain both available and performant. When correctness depends on…
Consensus is what prevents distributed systems from fracturing into multiple, conflicting realities. It ensures not just that replicas hold the same data, but in the same order, under the same history. This requires more than copying data between nodes. It requires coordination. It requires leadership. In consensus protocols like Raft,…
In my last blog, we looked at how the Write-Ahead Log (WAL) underpins durability across different replication designs. But it’s equally important to understand why, in the world of consensus, the same idea is called a replicated log instead. A Write-Ahead Log (WAL) remembers what happened locally. A replicated…