Day 10
Distributed Consensus Protocols (Raft & Replicated State Machines)
How a cluster of unreliable servers agrees on one ordered sequence of events, using leader election and a replicated log.
Distributed SystemsConsensusConsistency
Start lesson Daily System Design
Learn system design.
One concept a day.
Architecture diagrams, real-world examples, trade-offs, and interview questions for each concept.
9 lessons
Interview questions
All lessons
Day 09
Distributed Unique ID Generation (Twitter Snowflake & UUIDv7)
How to generate unique, roughly time-sortable IDs across many servers without a central database.
Distributed SystemsDatabasesIdentifiers
Start lesson Day 08
Message Queues vs. Event Streams (RabbitMQ vs. Apache Kafka)
When to use a queue that deletes messages after delivery, and when to use a replayable, partitioned event log.
MessagingKafkaAsynchronous
Start lesson Day 06
CAP & PACELC Theorems (Consistency vs. Availability)
What a distributed data store must give up during a network partition, and what it trades off the rest of the time.
Distributed SystemsConsistencyAvailability
Start lesson Day 05
Consistent Hashing & Virtual Nodes
Add or remove servers while moving only a small fraction of keys, instead of reshuffling almost everything.
Distributed SystemsPartitioningScalability
Start lesson Day 04
Database Sharding & Horizontal Partitioning
Split one logical dataset across many databases when a single primary can no longer keep up with storage or write volume.
DatabasesScalabilityPartitioning
Start lesson Day 03
Database Replication & Read/Write Splitting
Scale reads and survive failures by copying data to replicas and routing queries by type.
DatabasesAvailabilityConsistency
Start lesson Day 02
Caching Strategies & Invalidation Patterns
How in-memory caches speed up reads, the main read/write patterns, and how to keep a cache consistent with the source of truth.
CachingLatencyConsistency
Start lesson Day 01
Load Balancing (Layer 4 vs. Layer 7)
How load balancers spread traffic across servers, and when to route at the transport layer versus the application layer.
NetworkingScalabilityReliability
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