Mail file format..

Hi Guys

Our old Virtualmin servers (CentOS based, about 4 years old) stored email in a single large file for each user - but I’ve just setup a couple of new Ubuntu servers that we’ll be migrating to and noticed that email on the new server is stored as invidual files for each email.

How do I change this, so the Ubuntu is also stored in a single file? I’m hoping it will make the migration easier.