Scalable database driven web site - Advice needed

I should build a system containing a database (mysql or maria) and a web site based on Nginx with pure php7.

  • The developers should get their own system with a small demo database on their computer (notebook).

  • The beta stage should be on Digital Ocean as one droplet.

  • Production stage should be two droplets (copied from beta stage), one for database only, the other one for web site.

  • scaling should be done by multiplying the droplets and combine them.

What are your advices to that project in regard of the setup from beta to scaling?
Are there any pitfalls I should take care of?
Are there any documentations that would help me to figure out more details?

MySQL itself does not scale well. You may consider using, which could scale MySQL by sharding. You may consider Cassandra if you can use NoSQL.