Easy Learn
A complete, beginner-to-production tutorial on sharding versus replication in distributed databases: why the topic matters and the short history of horizontal scaling, the three failure modes of a single database and how each technique attacks a different one, precise definitions of nodes, replicas, and shards, a CAP-theorem foundation with consistency…
A complete, beginner-to-production tutorial on database replication – what it is, why it exists, how it works internally, and how it is used in every serious modern system. Covers the notebook analogy and the full history from 1970s single-machine relational databases through the birth of primary-backup in the 1980s-90s, the…
A complete, beginner-friendly walkthrough of what a disadvantage of microservices actually means in practice: the toy-box analogy for one giant box versus many small boxes; a short history from 1990s-2000s monoliths through the 2011-2014 James Lewis and Martin Fowler microservices article; the specific pains that microservices tried to fix (slow…
A first-principles guide to data sharding: what it is, why systems need it, and how they decide where data lives. Covers all five common strategies (range-based, hash-based, consistent hashing with virtual nodes, directory-based, and geographic/attribute-based) with worked Java code, sequence and ring diagrams, and honest trade-offs. Includes the routing architecture,…
A complete, beginner-friendly guide to database sharding. Covers: what sharding is and its history, the problem it solves (single-server scaling limits, vertical vs horizontal scaling, sharding vs replication), the core vocabulary (shard, shard key, logical vs physical shard, shard map, rebalancing, cross-shard queries), production architecture and routing options, the five…
A complete, from-zero, book-style tutorial answering “what is the main advantage of microservices over a monolith?” — with analogies, diagrams, Java code, and real production stories from Netflix, Amazon, Uber, Spotify, and the Amazon Prime Video counter-example. Covers history, the ShopEasy motivation example, core concepts (coupling, cohesion, bounded contexts, deployment…
A complete, plain-language guide to Service-Level Agreements (SLAs): what they are and where they came from, the business problem they solve, core vocabulary and precision (why 99.9% vs 99.99% matters), the eight-part anatomy of a real SLA document with a sample clause, the three distinct SLA / SLO / SLI…
A complete, beginner-friendly guide to the real reason behind the whiteboard in a system design interview. Covers: a short history of the whiteboard round, why words alone fail, what interviewers are secretly evaluating, the core vocabulary (system design, architecture diagram, component, data flow), the anatomy of a great high-level diagram…
A complete, beginner-to-advanced tutorial on when to stay with a monolith instead of splitting into microservices. Covers the one-house vs small-city analogy and the full 1990s-through-mid-2020s history (single monolith, SOA, microservices popularised at Netflix and Amazon, the industry-wide adoption boom, then the correction toward modular monoliths); the real motivations for…
A complete, beginner-to-advanced guide to finding the one slow component that limits a whole system: the honey-bottle analogy and why bottleneck hunting separates senior engineers from junior ones; five reasons systems develop bottlenecks over time (traffic growth, data growth, hidden feature work, contested shared resources, hardware limits); precise vocabulary (latency,…