For local backup, is there an app that will automatically span multiple drives? i.e. I have a 40TB RAID to backup locally to a series of drives… some 8TB, some 4TB, whatever. Don't want to segment the files on the main 40TB, just want backup to fill backup drive 1, then 2, etc

I would love to know if there is a good way to do this. I've done this before by turning a pile of external hard drives into a "JBOD RAID" with the built in mac Disk Utility. Not quite the same cause if you unplug one drive it all disappears.

yeah the JBOD is dangerous. One fails and you lose everything.