SQLite is more than enough for my needs, I think. In the best of worlds we will have no more than a few thousand customers after we get up and running. But I'm not sure what to do about the database file, which is of course unencrypted. I will place it in a directory that is not accessible to web users and also make it invisible via .htaccess.
What's the best way to manage the SQLite data file? Encrypt, then gzip, then ssh it to a remote location once or twice a day using a cron job?