Databases are core to most software systems, and their design directly influences both scalability and performance. Here’s what every engineer should know:

Key Roles of Databases in Scalability

Horizontal Scaling: Distributed databases can be split across multiple servers (sharding) to handle large datasets and more users.

Example: A social media app splits user data among different servers by geographic region.

Load Balancing: Replicated databases share the workload and improve availability.