I’ve read the Multi-tenancy & databases thread, but it didn’t quite answer my specific question.
I’ve got an application that needs to scale to millions of users. Each user will be creating one or more “environments” that could be encapsulated cleanly in a stand-alone database whose overall size and write load will, in isolation, be small (maybe 5-20 small tx/minute peak). In aggregate the write load would probably be quite prohibitive (70k/s) for a single transactor, but trivial if divided down to a database per environment. The overall size of these instances might grow to something on the order of 1M datoms over time.
I understand that each database creates some level of overhead, but I cannot find any specific numbers that give an indication of the relative size of that overhead for cloud deployments.
What is a “realistic” number of these “small databases” that could run in Datomic cloud on a pair of i3large instances, for example, without most of the resources being used by the overhead itself?