Backup to iCloud

What you are describing isn't exactly how iCloud works.

Apps need to be iCloud aware in order to be able to utilize iCloud and therefore save files to iCloud.

An application that is not iCloud aware can't save files to iCloud (easily at least)

https://support.apple.com/kb/PH12519?viewlocale=en_US&locale=en_US

iCloud is not a Cloud backup system per se like Carbonite where you can really specify what you want backed up.

If you already have a DropBox account and all the documents that you want to backup fit in your DropBox, I'd use that as it is a) backing up for you and b) available just about anywhere.

SR

 

Actually... iCloud Drive can be used as the OP describes ("old" Documents in the Cloud works the way described in the previous post). http://www.apple.com/support/icloud/icloud-drive/

Enable iCloud Drive on the Mac (if it's not already enabled) and it'll appear in Finder (and File > Save dialogs), just as Dropbox does. You can create folders and place whatever file type you wish there. While not an exact duplicate of Dropbox, it can be used essentially the same way (Dropbox's image-storage features, however, are not duplicated, as iCloud Photo Library performs that function).

Something you may not appreciate about both iCloud Drive and Dropbox (presuming you use the Dropbox app, rather than the web page) - the files you place there are not just in the cloud - they're also cached on the HDD. That's done so that you can work with those files when you don't have an internet connection. So while it doesn't hurt to keep the same file in Documents and iCloud Drive, it's a bit redundant and takes up more HDD space than you may think. And you'll have fewer issues with having dissimilar versions of the same document.

But I do concur that iCloud is not a complete backup solution. For backup to a local (external) drive, Time Machine is built into OS X. https://support.apple.com/en-us/HT201250

There's a key difference between keeping copies of documents, and backing up an entire system. One saves your documents, the other gets your entire computer back to the way it had been - apps, configurations and preferences, and all those little things you may have neglected to copy. Whether you choose Time Machine, Carbon Copy Cloner, Carbonite, or something else... there's no substitute for a full system backup if and when you have a hard drive failure.