As Ken mentioned infrastructure is not specific to Mezzanine.
Scaling is based the level growth you're experiencing.
You don't want to build your initial Mezzanine infrastructure for the million users you don't have yet, nor the engineering team you don't have yet.
I start out mezzanine projects on AWS: using an EC2 instance for the app, an RDS instance for the database, an elasticache instance for the caching layer, and S3 / cloudfront for file storage.
That approach is almost over optimization for something brand new. But it also can handle the pleasant surprise of your app gaining traction.
Once your app gets to a certain point the infrastructure needs to change. There is also DevOps if you plan on having an engineering team iterate on your code base.
Just get your App up and running to test your hypothsis first (that people will actually visit your project)
That said, if you're at a funded startup, or you have a large tribe on deck and ready for your app, check out some dev ops and infrastructure courses on Udemy and use Mezzanine with it.