Design a comprehensive distributed system architecture for a platform that needs to process petabytes of data daily with sub-second latency requirements. Your design should include: 1) Component breakdown with specific technology recommendations, 2) Data flow diagrams for normal operations and failure scenarios, 3) Consistency and availability tradeoffs with justifications, 4) Scalability approach for horizontal and vertical scaling, 5) Security considerations at each layer, 6) Monitoring and observability strategy. Provide detailed reasoning for each architectural decision, including potential alternative approaches you considered but rejected.