Grokking Scalable Systems for Interviews

1 Course Overview
2 Who This Course Is for
3 What Is Negative Caching and When Should You Cache 404 or Empty Results
4 What Is the Difference Between Soft TTL and Hard TTL, and Why Does It Matter
5 How Can a Bloom Filter Reduce Cache or Database Load
6 What Is Distributed Locking for Cache Rebuilds, and How Does It Prevent Cache Stampedes
7 What Are Sticky Sessions Session Affinity and When Should I Avoid Them
8 What Is the Difference between Liveness Checks and Readiness Checks in Load Balancers
9 What is Global Server Load Balancing GSLB and How GeoDNS and Anycast Work
10 What are the Main API Pagination Strategies offset, cursor, keyset, and When Should I Use Each
11 What are HTTP Conditional Requests ETag, If‑None‑Match, Last‑Modified and How They Reduce Load
12 What Is the Difference between Rate Limiting and Throttling and Quotas
13 What Are Idempotency Keys and How to Implement Them Safely for Payments
14 What are SQL Isolation Levels Read Committed, Repeatable Read, Serializable, and What Anomalies Do They Prevent
15 What Is a Write‑Ahead Log WAL, and How Does It Ensure Durability
16 What Is the Difference Between Synchronous and Asynchronous Replication, and When Should I Use Read Replicas
17 What Is MVCC Multi‑Version Concurrency Control, and How Does It Enable Concurrent Reads and Writes
18 What Are Safe Patterns for Online Schema Changes vs
19 What is Little’s Law and How to Use It for Quick Capacity Estimates in System Design
20 How Can I do Back-of-the-Envelope Sizing for QPS, Bandwidth, Storage, and Peak vs
21 What are Cold Starts and Warm Starts, and Why Do They Matter for Performance
22 How Do I Choose a Good Shard Key and Avoid Hotspots Bucketing and Key Randomization
23 What Are Range Sharding, Directory‑Based Sharding, and Geo‑Sharding, and What Are the Common Use Cases
24 What Is the Difference Between Rendezvous Hashing and Consistent Hashing, and When Should I Use Each
25 What Do At‑most‑once, At‑least‑once, And Exactly‑once Delivery Semantics Mean
26 What Are Idempotent Producers And Consumers, And How Do De‑duplication Keys Work
27 What Is Message Ordering, How Do Partition Keys Affect It, And When Can Ordering Break
28 What Are Windowing And Watermarking In Streaming Systems, In Simple Terms
29 What Is Quorum N, R, W, And Why Does R W N Give Strongly Consistent Reads
30 What Are Common Conflict Resolution Strategies Last‑write‑wins, Vector Clocks, Logical Clocks
31 What Are Read Repair, Hinted Handoff, And Anti‑entropy Merkle Trees In Eventually Consistent Systems
32 What Is The Difference Between SLI, SLO, And SLA, And Can You Give Simple Examples
33 What Is Opentelemetry, And How Do Traces, Spans, Metrics, And Logs Fit Together
34 What Is An Error Budget, And How Should It Guide Release Decisions
35 What Are The Trade‑offs Between Server‑stored Sessions And JWTs for Authentication
36 What Is The Difference Between TLS And MTLS, And When Is MTLS Appropriate For Service‑to‑service Auth
37 What Is Secrets Management, And How Do Environment Variables, KMS, And Vault Compare
38 What Is A Replay Attack, And How Is It Different from Idempotency Issues
39 What Are The Differences Between TCP, UDP, And QUIC, And When Should I Use Each
40 What Is The Difference Between A Forward Proxy, A Reverse Proxy, And NAT
41 What Changed From HTTP1.1 To HTTP2 To HTTP3, And What Are Head‑of‑line Blocking And Multiplexing
42 What Is the Difference Between Content‑Addressable Storage and Location‑Based Addressing
43 What Are Checksums and Etags, and How Do MD5SHA Compare to CRC for Integrity
44 What Are Hot, Warm, Cold, and Archive Storage Tiers, and When Should I Use Each
45 What Is the Outbox Pattern, and How Does Change Data Capture CDC Work at a High Level
46 What Is CQRS Command Query Responsibility Segregation, and When Should I Consider It
47 What Are the Differences Between a Circuit Breaker, Retry With Backoff, and Rate Limiting
48 What Are RPO and RTO, and How Do They Differ in Disaster Recovery Planning
49 What Is the Difference Between Active‑Active and Active‑Passive Architectures
50 What Is Graceful Degradation, and How Do Feature Flags Help Availability
51 What Are the Differences Between UUID, ULID, KSUID, and Snowflake IDs, and How Do I Choose
52 How Do Snowflake‑Style IDs Work Timestamp, Worker, Sequence, and What Problems Do They Solve
53 What Is the Difference Between Wall‑Clock Time and Monotonic Time, and Why Is Clock Skew Hard
54 Final Words
55 Key Takeaways
56 What To Learn Next