Distributed Systems Series — Part 5.6: Scalability & Performance The Difference Between a System That Degrades and One That Collapses Traffic is never uniform. Every distributed system experiences load spikes — viral events, marketing campaigns, coordinated usage patterns, or simply the natural rhythm of peak hours. The engineering question is not whether spikes will occur … Read more
Distributed Systems Series — Part 5.5: Scalability & Performance The Most Powerful and Most Dangerous Scalability Technique Caching is the highest-leverage performance technique available in distributed systems. A cache hit costs microseconds. A database query costs milliseconds. A cache that absorbs 90% of read traffic reduces database load by 90%, reduces read latency by an … Read more
Distributed Systems Series — Part 5.3: Scalability & Performance The Write Scalability Problem Post 5.1 established that data scalability — the ability to handle growing data volume — is a distinct problem from load scalability. Post 3.8 established that write throughput in leader-based replication is bounded by the leader’s capacity — reads scale with replicas, … Read more
Distributed Systems Series — Part 5.2: Scalability & Performance Why Latency at Scale Is a Different Problem Post 5.1 established what scalability means and identified Amdahl’s Law as the mathematical ceiling on parallelism. This post addresses the latency dimension of scalability — specifically why latency behaviour at scale is fundamentally different from latency at low … Read more
Distributed Systems Series — Part 5.4: Scalability & Performance Load Balancing Is Not One Algorithm Post 5.3 established that partitioning creates multiple independent nodes, each owning a subset of the data and serving reads and writes for that subset. Load balancing is the mechanism that distributes incoming traffic across those nodes — and across the … Read more
Distributed Systems Series — Part 5.1: Scalability & Performance What Scalability Actually Means Parts 1 through 4 of this series established how distributed systems work correctly and survive failures. Part 5 addresses the final dimension: how do systems handle growth? Scalability is one of the most overused and least precisely defined terms in software engineering. … Read more