More than likely, you will need to do the backup without the import items. It will actually be small, probably much less than 1 GB.
You can then use another program to backup your import items to your other computers.
You should probably look at the resolution you are scanning documents. 30GB is huge. I have >4000 patients, have been using the program in one office for 7 years have imported all the paper charts and the file is <3 GB.