Scaling Writes

Scaling reads is relatively straightforward. You add caches to absorb repeated requests and read replicas to distribute the load. Scaling writes is a fundamentally different challenge. Every write must eventually reach the authoritative copy of the data, and in a traditional database architecture there is exactly one primary node responsible for accepting writes. You cannot simply "add more copies" the way you can with reads, because every copy needs to agree on the order of changes. This lesson covers what happens when your primary database can't keep up with write volume, and gives you a ladder of strategies to climb from the simplest fix to the most complex.