(Newbie) Storing lage amounts of user data

(Newbie question)  So, if an application has only a couple of dozen users, but there are many hundreds of thousands of records to be stored, what is best practice for storing: - The application (in the 'internal’ Mendix database)? - The user data (in an external database, like MS SQL? Azure?)  
1 answers

Mendix is well capable of storing hundreds of thousands objects in an entity, so by itself this is no reason for storing the user data in an external database. Mind setting the correct indexes, which the “MxAssistent Performance Bot” will help you do.

If need be use OQL-commands to make retrieves faster and implement some sql-delete statements if you run into problems deleting large number of objects.