Look up "Prevayler" and the "system prevalence" pattern. It introduces occasional data journaling, and so it exists somewhere in between "serialize and persist

Look up "Prevayler" and the "system prevalence" pattern. It introduces occasional data journaling, and so it exists somewhere in between "serialize and persist the whole thing at once" and a full blown DBMS. But I've experimented with system prevalence in the past and decided that just "serializing and persisting the whole thing at once" like you've mentioned was simply a better solution.