Scale Vertically (Bigger Box) Versus Scale Horizontally (More Boxes)
TradeoffMidSeniorUpdated
Single Postgres instance approaching CPU saturation as traffic grows.
Short answer: Scale vertically (bigger box). Vertical is the simplest first step for relational DBs: no sharding, no app changes.
The Two Options
A
Scale vertically (bigger box)
B
Scale horizontally (more boxes)
Drill This: Your Pick First
The Better Pick
Option A
Scale vertically (bigger box)
Vertical is the simplest first step for relational DBs: no sharding, no app changes. Modern cloud DBs scale to enormous sizes.
When the Other One Wins
Scale horizontally (more boxes)
Once you hit the largest instance available or write-throughput limits, horizontal (read replicas, sharding) becomes necessary.