---
answer: direct
beat: system-design
source: 1 article · updated: August 17, 2026
---

When should I choose LSM-trees over B-trees?

Use LSM-trees for write-heavy workloads with high throughput targets (millions of writes/sec) where occasional read latency spikes are acceptable. Use B-trees for balanced or read-heavy workloads where consistent query latency matters more than write throughput, like OLTP systems.

Answered in

LSM-Trees vs B-Trees: Why Cassandra Chose Sequential Writes

B-trees seek random disk positions. LSM-trees buffer in memory and flush sequentially, converting random I/O into sequential writes for millions of ops/sec.

Crashtech Editorial August 17, 2026 System Design

Read the full analysis

Other questions this article answers

More system design questions

Every answer on Crashtech is written by the editor of the article it comes from — never auto-summarised. Browse all answers or the System Design beat.