Is it reasonable to host my database and NodeJS application on the same server?
What are the pros/cons?
I don't think horizontal scalability is a concern, since RethinkDB supports clustering. I'll be using Dokku on a DreamHost cloud server (aka DreamCompute), and will eventually switch to Flynn for scaling purposes.
It is perfectly reasonable. If it makes sense or not, depends on the metrics of usage.
For scaling purposes, if your application and database need to scale in parallel, it has sense to keep the two services in the same server since scaling instances of that server will scale both services.
If instead you need to scale your application and database in an asymmetric way, separation might be a better solution as it allows for a more flexible handling of resources.
