Sounds like a good move, though I don't know how the site's data was structured before (though from experience I'd hazard a collection of different and interlinked pieces...) Having a single database for everything can cause its own issues too, particularly when scaling enormously. Happy to discuss "data as a service" and other concepts if that will help - one thing at a time though!
Serialised s-expressions. We're about three orders of magnitude from that problem. We've considered SQL-as-a-service; at some point, it may be cheaper and faster than using a VM host. But it'll almost certainly be SQL. Our data is relational (like 99% of data), and we'll probably never see the scale where it becomes infeasible. Facebook uses SQL with peaks of 13 million transactions/second. We're currently on the order of 1 transaction/second.how the site's data was structured before
particularly when scaling enormously
Happy to discuss "data as a service" and other concepts if that will help