I'm sorry for yet another "how do I back up..." thread, but I couldn't find a suitable answer in any of the related threads. I'm looking for some advice on keeping a large external-HDD media library backed-up. Here's my situation: I've got a MBP with a 1TB internal SSD. I do a lot of audio work, and over the past several years, I've accumulated several 1TB external drives for storing my raw and processed audio files. I've been manually managing back-ups by plugging in two external drives and dragging and dropping files twice to be sure my files are on two external drives before deleting from my internal drive. It's not only cumbersome, but prone to errors. Now that some of those external drives are 7-8 years old, I'm thinking about consolidating everything onto one 4TB or 6TB drive and then keeping that backed up (mirrored). I know that for those with deep pockets the possibilities and configurations are nearly limitless, but given my rather limited budget, what I'd *really* like to do is get two of these WD MyBook 8TB units, use them in either striped RAID0 or JBOD mode, and have a way to keep them mirrored. (Given that a failure of a unit's internal RAID 1 controller could lead to data loss, I don't want to rely on that.) I think it's theoretically possible to use Time Machine to back-up an external drive, but I don't want my external drive backups mixed in with the back-up of my MBP's internal SSD. Would Carbon Copy Cloner (CCC) give me the right tools to keep the two units in line with each other? Especially now that Apple is betting on people opting for smaller internal SSDs and storing most data externally, surely there must be some reliable way to keep external drives backed up on a rolling basis? (I.e., without making a periodic clone of the entire drive every now and then.) I'd be grateful for any advice. Thanks!