DBC Backup 2 is a safe & simple way to schedule regular WordPress database backups using the wp-cron batch jobs.
It makes sense to me to keep the SQL database backup where you will most likely need it if something goes wrong. Many web hosts provide a large amount of free space for you to store files. So rather than having to pay someone else for storing your database backup you can use the free space you already have.
Not really, server based back-ups are only unsafe if your server is prone to fail or poorly protected from hacking.
That's easy, the plugin creates a .htaccess file in the backup folder. You can open this file and add to this code. The backup folder is protected against browsing or direct file access.
No, as this would mean any anonymous user with the link could download your backup file. This would make things very insecure for you.
Because Gzip and Bzip2 are not installed on your server.
WP-Cron is different to server cron as it requires WordPress to trigger the batch jobs. This means, for example if you have no visitors on your site at the time of backup then the backup will run the next time someone browses your site. The same problem also happens with things like scheduled posts.
Yes, seriously. You can read up on wp-cron.
About 2 years I've been using this and yes, a few times I've used a backups to build a fresh website.
Yes, it will create a backup of all blogs and sub-sites. In the future I hope to make it work for just selected blogs.