Design a comprehensive microservices architecture for an application expecting 10 million daily active users with 99.99% uptime requirements. Include: (1) service decomposition strategy with clear domain boundaries; (2) inter-service communication patterns handling partial failures; (3) data consistency approach across distributed services; (4) deployment strategy with blue-green canary releases; (5) observability and monitoring framework; (6) autoscaling policies based on different metrics; (7) security model including authentication, authorization, and encryption in transit and at rest; (8) disaster recovery plan with RPO/RTO targets. Justify all design decisions with technical reasoning.