I'm kind of shocked that more people aren't trying to do this honestly. About a decade ago, there was a great program called Norton Ghost that was very popular with Schools, Companies, Universities, etc. Or in other-words, where there's people who could really mess computers up that you don't want messed around with......programs uninstalled, possible malicious items accessed, etc, oh and Public Library's definitely use it too (around me anyway). Norton Ghost was just a windows product though and it's not been used much in the last few years. Ghosting your server would definitely allow you to re-image a computer in 30mins or less. It's 10x easier and MUCH faster than fixing and undoing all the things someone could've messed with.
Everyone else here is referring to products like Crashplan (which is an excellent backup provider at a great price), but that would still require you to reinstall the OS etc, whereas you could just boot into rescue and write the image file directly to the disk, reboot the server, and then.....voila!. As long as your hardware is still the same, you just got an image restored that s an exact copy with 100% of all the files on it when you made the image.
1. For backing up just the folder with all your files being seeded or leeched > I'd say you'll be fine with ACD Unlimited, Google Drive Unlimited, or Crashplan. I use all 3 because they're not expensive at all and a house fire could always scrap my entire RAID array. I use Arq 5 to backup to ACD and Google Drive. With Crashplan, I use my own encryption key. Boxcryptor is a "freemium" alternative to Arq, that works on Mac, Windows, and Linux.
2. If you want a product like Norton Ghost that'll work for you, there's 2 good alternatives: Clonezilla (http://clonezilla.org/) & FOG (https://fogproject.org/)
Hope that helps!