System Atlas

First principles, identifying bottlenecks, every component exists to solve a problem 

Read replicas, cache, latency, consistency 

Edge delivery, object storage, stateless architecture 

Regional failures, multiple data centers, disaster recovery 

Asynchronous processing and observability 

Vertical scaling isn't enough, partitioning data 

Ring architecture minimizing key movement 

Consistency, Availability, Partition Tolerance 

Quorum, N-W-R, and distributed system promises 

Five databases, five different CAP theorem trade-offs 

Distributed locks protect decisions, not databases 

Redlock, expiring leases, and fencing token safety 

Synchronous request chains and cascading failure risks 

Thread exhaustion, cascading failures, and idempotency keys 

Message brokers enable decoupling, buffering, and scaling 

Delivery guarantees, idempotency, and the outbox pattern 

Dual-write problem, CDC, outbox, event sourcing patterns 

Two-Phase Commit coordinates atomic distributed transactions 

Three-Phase Commit adds a timeout-based safety layer 

Saga pattern, orchestration versus choreography trade-offs