1 — Relational Databases

Site Reliability Engineering: From Foundations to Internet-Scale Systems

The complete 184-chapter, 15-part Site Reliability Engineering curriculum — from Linux internals and distributed-systems theory through reliability engineering, observability, incident response, platform engineering, and Staff/Principal-level MAANG interview preparation, ordered the way SRE expertise actually develops rather than as a topic index.

2 — NoSQL Systems

The consistency, availability, and schema trade-offs different NoSQL models make, and why 'NoSQL' is really a dozen different reliability postures wearing one name.

3 — Distributed Databases

How a database spreads data and consensus across nodes, and the CAP-theorem trade-off it's making on your behalf whether or not that's documented.

4 — Replication

Synchronous vs. asynchronous replication, and the replication-lag failure mode that turns a 'read your own write' assumption into an intermittent bug report.

5 — Sharding

Partitioning data across nodes to scale past a single machine's limits, and the resharding operation that's usually the actual hard part.