Multi-region read scaling
Your task
Design read-scaling for a multi-tenant SaaS app (project management) where the primary DB is in us-east but 40% of users are in Europe and complain about slow page loads. You want to serve European reads locally from replicas while keeping correctness: a user who just saved a task must see it on the next page load, and dashboards can tolerate a few seconds of staleness. How do you architect the replica topology and routing?
It covers
- Read replicas
- Replication lag
- Follower reads