Step 1: Fundamentals

• Serverless vs Serverful Architecture
• Horizontal vs Vertical Scaling
• Threads, Pages, DNS, Request-Response Cycle
• How the Internet works

Step 2: Databases

• SQL vs NoSQL
• Neo4j, MongoDB, etc.
• In-memory databases
• Data replication and migration
• Data partitioning and sharding

Step 3: Consistency & Availability

• Eventual, Quorum, Causal, Linearizable consistency
• Isolation levels: Read Uncommitted, Read Committed, Repeatable Read
• CAP Theorem: trade-off between consistency and availability

Step 4: Caching

• What is caching?
• Redis, Memcached
• Write policies: Write-back, Write-through, Write-around
• Replacement policies: LRU, LFU, Segmented LRU