I did a project for a big telecom in Brazil where they kept everything in one massive Oracle database that ran out of 2 oracle refrigerators[1]. They kept freaking logs on the database, like normal application level logs.

DBA would go around screaming if you were logging too much stuff. I assumed they had some sort of periodic cleanup because I couldn't see that stuff being practical long term.

Technically it was 2 databases, one was a read replica for longer running data analysis of course.

That telecom has at least 100 million paying customers (maybe much more). I don't see they ever moving away from Oracle, they are more likely to go bankrupt than ever leaving.

[1]: Oracle RAC: https://en.wikipedia.org/wiki/Oracle_RAC