You can find some information on that here: https://www.ory.sh/docs/ecosystem/deployment#data-storage-and-persistence Not sure about concerns though.

I saw this actually and it was the primary reason I started thinking "Is there a reason I can't just run these all under one postgres instance until I figure out how to drop the database entirely?"

@helpful-keyboard-62948 one postgres instance can have many databases. I would just create a separate db per application as a good practice e.g. you might not want your hydra instance to go down when something goes wrong with the kratos db tables. As @worried-kitchen-94392 pointed out, from a technical point it will work, it's more of an operational problem.