Change default data directory for new users


I have a running instance of Nextcloud for my association.

It has an insternal SSD that me and the other admin are using. This one is pretty limited (100Gb) and contain the data directoty /var/www/

We also have an external SSD that we use as a common storage, and which is configured with the “External Storage” extension.

Now, we plugged a second external SSD where we would like to put the data of the new users, all the members of the association.
I created a folder /var/www/ and I mounted the external drive on it.

Now I’d like to set up the default data directory to /var/www/ for the new members only, without moving the data of the existing users.

Is there a way to do this ?

Thank you very much