Droplet with large number of sites

I’m currently building a system where the entire functionality is stored in one, core system and clients hosted on the same droplet simply symlink to index.php and only really have media directory with each client for their own media.

Now - I’m trying to figure out whether it will work with say 500 / 1000 sites - each one will have its own dedicated database, plus access to the core database for common features.

Could anyone give me some advice on what / how should I configure droplet as?

I believe nginx sockets might cause a problem (which I have already had a chance to experience) and I’ll probably have to use TCP - I’ve followed these instructions earlier today: https://rtcamp.com/tutorials/php/fpm-sysctl-tweaking/

Now - would the database also need to be set up to use TCP?

In general - do you think that single (large) droplet would be capable of handling this sort of system? I understand that it depends on many factors like traffic to those sites etc. but some advice on how to handle this would be very much appreciated.