Sharding
Range / Hash · Horizontal partition
Replication
Leader‑follower · Multi‑AZ · Read replicas
Caching
Redis / Memcached · LRU · Cache‑aside
Data Pipeline
CDC · ETL · Stream processing (Flink)
SQL
PostgreSQL · ACID · Complex joins
NoSQL
MongoDB / Cassandra · Document / Wide‑column
Object Storage
S3‑compatible · Blob · CDN origin
Data Consistency
Strong vs. Eventual · Quorum · Write‑ahead log
Backup & Recovery
Point‑in‑time · Snapshot · Disaster recovery