It's really easy to quickly outgrow your internal drive if you've got a substantial iTunes library. And, with all that metadata involved, the last thing you want to do is lose your ratings, comments, whatever.

Don't despair. It's actually really easy to move your iTunes library with iTunes itself. That's right: no Finder, no SuperDuper!, no nothing. And iTunes takes care of all the details!

Here's how:

  1. Make sure the drive you want to put the library on is connected. The drive can be a network volume, local volumes, whatever -- just make sure it's mounted and ready to go.

  2. Open iTunes and choose iTunes > Preferences. In the Advanced tab, choose the new location for the library.

At this point, you could stop, and all future music/movies/whatever you add to iTunes will be stored in the new location: in essence, your library will be on more then one drive, and you can repeat the above as the new location fills as well.

But, if you want to move your existing music and videos into the new location:

  1. Choose Advanced > Consolidate Library. iTunes will copy all of the music from all the various previous locations into the new library location you selected above.

When it's done, make sure you're happy with what you've got. You can then delete the old iTunes Music folder in ~/Music/iTunes. But don't delete the iTunes Library or itunes Music Library.xml files: those must remain where they are.