If you’ve got a tiny hard drive on your Mac and a large-capacity iPhone or iPad (or both!), you might worry that you’re about to run out of space due to all the stuff you want to back up from your iOS device to your OS X one.
You won’t have to worry any longer. This trick makes your Mac back up your iPhone or iPad to an external drive, which will ensure you never run out of space to keep your data backed up.
Here’s how.