Well, my music is kept on a separate drive from my computer, and that drive is backed up to a third, disconnected drive. Additionally, having 2 ipods that are mirrors of each other means there are two more backups of the music files (although not named right). Lastly, all Amazon purchased music that was digital or autorip (not the physical only CDs or marketplace) is duplicated in the amazon Cloud, although often with poor metadata.

I'm current dealing with 40037 songs, 156.57 GB, on a 512GB iPod. The ammount of time it would take to upload that would be sizable.