System Design Acronyms

Atomicity, Consistency, Isolation, Durability — guarantees for database transactions.

Basically Available, Soft state, Eventually consistent — alternative to ACID for distributed systems.

If Partition → A or C; Else → Latency or Consistency. Extends CAP theorem for normal operation.

Conflict-free Replicated Data Type — data structures that merge automatically without coordination.

Log-Structured Merge Tree — write-optimized structure used in Cassandra, RocksDB, LevelDB.

Sorted String Table — immutable on-disk file of sorted key-value pairs. Core to LSM trees.

Write-Ahead Log — durability technique: write to log before applying to main storage.

Change Data Capture — stream database changes to other systems (Debezium, Kafka Connect).

Command Query Responsibility Segregation — separate read and write models for scalability.

Service Level Agreement / Objective / Indicator — reliability targets and their measurements.

Recovery Time Objective / Recovery Point Objective — how fast to recover and how much data loss is acceptable.