The only things not in the database that is can think of are uploads, which the docs you linked describe how to back up before an upgrade.
How about back up data in ACP
I am using redis and the data is stored in dump.rdb. Everytime when I want to backup this file, I need to ssh to the server. Is it possible to achieve this in ACP? I think it is a good feature. Or, is it possible to send this file every other week to some Email address?
With cron you can automate pretty much anything you can write a script for. That includes sending files around.