Cassandra
Apache Cassandra deep dive — cluster architecture and the ring, tunable consistency, the LSM-tree storage engine, and real-world case studies from Discord.
Dynamo & Bigtable Inheritance
How Cassandra inherits its cluster mechanics from Amazon Dynamo and its on-disk storage engine from Google Bigtable, replacing vector clocks with last-write-wins.
Cluster Architecture — Building Up the Ring
Build a Cassandra cluster from one node up — naive partitioning, consistent hashing, virtual nodes (vnodes), replication, and rack-aware placement, derived from first principles.
Consistency
Tunable consistency in Cassandra — why different operations need different correctness, quorums, R + W > N, read repair, and consistency levels.
Cassandra Storage Engine Internals
Why Cassandra uses LSM trees instead of B-trees — memtables, SSTables, the commit log, compaction, bloom filters, and the read/write paths.
Cassandra Data Modeling & Anti-Patterns
Query-first data modeling in Cassandra — hot partitions, partition-size limits, common anti-patterns to avoid, and when not to use Cassandra.
How Discord Stores Billions of Messages
How Discord scaled message storage to billions on Cassandra — data modeling, partitioning by bucket, and the operational lessons learned.
How Discord Stores Trillions of Messages
How Discord moved from Cassandra to ScyllaDB to store trillions of messages — GC pain, hot partitions, and a shard-per-core C++ rewrite.