Scaling a common application

Identify traffic sources

Where is the traffic coming from? Does the app have only web interface or does it have plans to go for a mobile app as well? Are planning to let users consume our APIs?

Server per traffic source and data

Depending on these questions it would be wise to have multiple servers. First to separate the web/mobile traffic (presentation layer) and the database on a separate server (to be able to scale the db if we need to).

But how? Guide us

Scaling is widely divided to two categories.

1. Vertical Scaling
2. Horizontal Scaling