I have a bunch of stuff I really don't want to loose. Pictures, and files. What would be a simple way to keep another copy of the stuff? Incase I get drive corruption and end up with loads of <unknownfile.1> or the lost+found stuff.?

How about 1 or 2 external (or internal?) hard drives that just mirror stuff? And what Docker would I use to handle that?

Simplest is an external drive, USB enclosure, mounted with Unassigned devices.

 

I have two of them.  I back up files once a week with a simple script which rsync several folders from my array to the external drive.  I use two drives, as I swap them every month or so, and keep one at work.

 

There are several backup utilities in Community Applications.  Easy to try them out, and see what you like.

To avoid extra power plugs and usb cords, I installed a 5.25 to 3.5 swappable drive bay.  The drive can be removed and installed in seconds.  I have two disks; one in the bay as unassigned device and the other is kept off-site.  They are rotated occasionally.  I just use rsync to perform a backup of each array disk to a diskX folder on the backup drive although I hear lucky backup is a good docker based backup solution.