Lesson 1Consistency types: strong, causal, eventual, read-your-writes, monotonic readsWe dive into distributed consistency types like strong, causal, and eventual consistency, plus read-your-writes and monotonic reads, explaining what they promise, the odd behaviours they allow, and how apps pick ones that fit what users expect.
Strong consistency guaranteesEventual consistency and convergenceCausal consistency and orderingRead-your-writes and monotonic readsChoosing models for applicationsLesson 2Distributed agreement methods: Paxos, Raft, and real-world uses (etcd, Consul)We introduce Paxos and Raft agreement methods and their jobs in picking leaders, copying logs, and changing setups, then link theory to practice with tools like etcd and Consul for metadata, locks, and teamwork.
Consensus problem and safety goalsPaxos algorithm core ideasRaft algorithm and log replicationCluster membership and reconfigurationUsing etcd and Consul in practiceLesson 3Splitting and dividing tricks: range, hash, and list-basedWe break down splitting and dividing tricks like range, hash, and list-based ones, zeroing in on spreading data, dodging busy spots, rebalancing, and directing traffic, plus how to pick and grow a trick as work and data increase.
Range-based partitioning designHash-based sharding and hashingDirectory and lookup-based routingRebalancing and resharding methodsAvoiding hotspots and skewed keysLesson 4Copying setups: leader-follower, multi-leader, and no-leader waysWe cover leader-follower, multi-leader, and no-leader copying, spelling out write and read routes, handling breakdowns, delays, and fixing clashes, and how each setup hits delay, flow, lastingness, and running trouble in worldwide setups.
Leader-follower replication flowsMulti-leader replication and conflictsLeaderless quorum-based replicationReplication lag and read consistencyOperational trade-offs of each modelLesson 5CAP rule and choices between consistency, availability, and split handlingWe look at the CAP rule and what it means for spread-out databases, making clear how consistency, availability, and split handling mix, and how real setups handle choices with practical designs and service targets.
Formal statement of the CAP theoremConsistency vs availability in practicePartition tolerance in real networksDesigning around CAP with SLAsLesson 6Network splits, delays, and breakdown types over wide area linksWe check how network splits, delays, and breakdowns show up over wide area links, covering timeouts, partial breakdowns, and split-brain, plus how to plan spotting, retries, and slowdown tricks to keep setups steady under pressure.
Characteristics of WAN linksDetecting partitions and timeoutsHandling partial and asymmetric failuresSplit-brain risks and mitigationGraceful degradation strategiesLesson 7Repeat-safety, retries, and at-least-once vs exactly-once meaningsWe explain repeat-safety and its part in safe retries, sorting at-least-once, at-most-once, and exactly-once meanings, and showing tricks for removing duplicates, tracking requests, and handling messages in shaky spread-out setups.
Defining idempotent operationsDesigning safe retry mechanismsAt-least-once vs at-most-onceExactly-once semantics limitationsDeduplication and request trackingLesson 8Shared work control: hopeful vs careful, MVCC, clash fixing methodsWe look at shared work control in spread-out databases, pitting hopeful against careful ways, explaining MVCC insides, and showing clash spotting and fixing methods that keep things right while allowing lots of shared work.
Pessimistic locking in distributed systemsOptimistic control and validationMVCC snapshots and version chainsConflict detection and resolutionDeadlocks, timeouts, and retriesLesson 9Setup shape tricks: one area, active-passive, active-active, and mixedWe describe physical rollout shapes for spread-out databases like one area, active-passive, active-active, and mixed tricks, and check their hit on delay, switchover behaviour, data sameness, and running trouble.
Single-region deployment trade-offsActive-passive failover patternsActive-active multi-region setupsHybrid and tiered topology designsLatency, RPO, and RTO considerations
