Design an IoT Time-Series Database (MongoDB)

Design a MongoDB schema optimized for storing and querying IoT sensor data with time-series patterns.

Functional Requirements

• Store readings from millions of IoT devices
• Support various sensor types (temperature, humidity, motion, etc.)
• Enable time-range queries and aggregations
• Handle device metadata and configuration
• Support real-time dashboards and historical analysis
• Alert threshold configuration per device

Non-Functional Requirements

• Ingest thousands of readings per second
• Efficient storage for time-series data
• Fast time-range queries with rollups
• Data retention policies and archival

Questions to Consider

• What document model optimizes for time-series data?
• How do you balance write throughput vs query flexibility?
• What bucketing strategy works best for your access patterns?