a git to get running
I almost praised you there, but I suspect you implied the other definition of git !
On Linux/BSD boxes (Mac too... it comes bundled with Xcode) .... git (the tool) is an incredibly handy tool for a multitude of purposes, but comes in particularly handy when you're messing around with config files.
Git your /etc dir and you can easily diff' the changes you've made from the base config.
Think of the issues for users with photo collections - Many Gb or Terabytes at stake. Me think's of air gapped systems (intenet disconnected), connected by Firewire and data transferred; say once a week, over night -
I'd say a combination. Online/Nearline in the sort of form you describe for efficiency, combined with Offline (DVD/Bluray) backups for long term security.