With all due respect, backing files directly to iCloud is somewhat out of date. It is far better to use the iTunes "Match" capability which essentially stores your entire music library in the iCloud and makes it available to any "i" device you own as well as to any computer running iTunes. It costs $25/yr for the subscription but it makes your collection available from virtually anywhere. The devices you use it on are not required to actually download the music files; they obtain them from the cloud and play them as they are being downloaded.