Although Apple iCloud allows you to back-up the most important data on your iDevices, the Apple iTunes is still the ultimate backup option, unless you opt to pay for additional iCloud storage. This is because it allows for the full backup of all your iDevices on your computer. The downside though is the prodigious amount of space it needs to back-up your iDevices. This presents a problem for those who are either using a very small drive (e.g. SSD), or have partitioned the boot partition to be small. The lack of storage space may force you, the user, to stop backing up your iDevices, and could potentially result in lost photos and videos should your iDevice fail for whatever reason. Apple has not seen it fit to provide us with a solution to the problem, but we have just the trick to allow you to use a separate partition or drive to store the iTunes backup files. Check it out! Link : ED#180 : How To Switch The Location Of The Apple iTunes Backup Folder
