When I bought my iMac last year, I foolishly thought that a 500GB hard drive would be plenty big enough. But you know what they say, you can never have too much storage and my recent regime of ripping DVDs into iTunes as well as upgrading a lot of my music to lossless files has meant that those 500 gigabytes have been getting used up pretty quickly.
I figured that I needed to locate my burgeoning iTunes library somewhere else, off of the iMac internal hard drive. I had a few options, and the one uppermost in my mind was Network Attached Storage (NAS). After discussing this with Olitee though, he was firmly of the opinion that this wasn't necessarily the best option. Not only was it expensive, it might not work exactly as I wanted it to. I'd still have to have iTunes running on my Mac in order to be able to get my files to my AppleTV and Airport Express. His answer was a big external hard drive, locally attached to my Mac instead.
However, the thing I liked about a NAS was that - if it was a two-bay one, with two separate drives inside - it would automatically mirror one drive to the other in case of failure. I wouldn't be able to do this with an external hard drive would I?
I've used Apple's Time Machine to back up my computer ever since it was first introduced in Leopard, and I love it. It's incredibly reliable. What I didn't realise though, is that Time Machine will not only back up your main Mac drive, but it can also backup up other attached drives (providing they are formatted for Mac), so clearly, if done correctly, I could get Time Machine to backup my external iTunes library in addition to my main Mac drive.
So, learning from my "you can never have too much storage" lesson, I decided to go the whole hog and get two new drives - a 1TB for my iTunes library, and a 2TB for Time Machine.
Moving your iTunes library is reasonably straightforward, but there are a few potential pitfalls along the way - things have to be done in a certain order. You can search for "moving iTunes to external drive" if you want some more in-depth tutorials on the subject, but here's how I went about it.
Firstly, because I wanted Time Machine to be able to backup my iTunes drive, I needed to format it for Mac use. By default, most external drives come preformatted as FAT32, and rather stupidly, the ones that are Mac formatted cost more money?!
Anyway, you need to fire up Disk Utility, choose your drive in the left-hand column (make sure you choose the right one!) and then go to the "Partition" tab. I only wanted the one partition, so I chose this from the dropdown and ensured "MacOS Extended (Journaled)" was selected. Hit "Apply" and in only a few seconds you have a freshly formatted drive, ready to go.
The important thing to realise at this point is that you CANNOT just drag-and-drop your iTunes folder onto this new drive and expect it to work. It won't. You need to let iTunes do your housekeeping for you - that way the iTunes program can keep track of what is going where.
Needless to say, before you start messing with any of this, make sure you have a backup in case things go awry.
Then, in iTunes, you need to go to the File menu, and then choose "Library" -> "Organise Library".
From here you'll get a dialog giving you two check boxes - the lower of the two says "Reorganize files in the folder iTunes Media". If you've already got your library set up this way, then it will be greyed out and you won't be able to click it, so you needn't worry about this step. If, like me, you didn't have it this way, you can check this box at this point. DON'T choose the upper "Consolidate files" checkbox just yet - that comes later! Click "OK" and iTunes will set everything up in neat subfolders for you, in a central repository called "iTunes Media", subdivided into music, movies, TV shows etc. To be clear, you don't HAVE to do this - you can leave your folder structure as is, but to my mind allowing iTunes to set it up makes the next steps easier.
The next part is to tell iTunes that you want to move your library somewhere else. You do this via the iTunes "Preferences" option. Go to the "Advanced" tab, and you'll see "iTunes Media folder location" at the top.
Click the "Change" button and navigate to your external iTunes drive (I named mine, rather imaginatively, "iTunes"). You need to create a folder inside this drive for your media files, so create one at this point using the "New folder" button. You can name this new folder anything you like, but I opted for the default "iTunes Media". Click okay, and then ensure both the "Keep iTunes Media folder organised" and "Copy files to iTunes Media folder when adding to library" checkboxes are ticked. Click "OK".
Now comes the slightly scary bit. Go back to the iTunes "File -> Library -> Organise library" menu, and this time check the "Consolidate files" box. Click "OK", and iTunes will warn you that it's about to copy everything into the new location and that this cannot be undone. Click "OK", and the long and arduous task of moving everything will commence. This could take minutes or hours, depending on the size of your library.
Bear in mind that this does not remove your original media files from their previous locations - it copies them, not moves them. This means that you'll have all your music, movies and so on in two locations now - the new one, and the old one. Clearly the object of the exercise is to free up space, so you need to find your original "iTunes Media" folder and drag it to the trash. It's VERY important not to trash any of the other iTunes files - just the media folder. The other files "iTunes Library.itl", "iTunes Music Library.xml" etc are vital to the correct operation of iTunes. If you get rid of these, you'll lose all your play counts and playlists.
Quite iTunes, and then restart it. If you've done things correctly, iTunes will simply restart without protest. If it does, then you can empty the trash, deleting your original media files and freeing up all that lovely drive space!
For most people, that will be quite enough tinkering. Everything will work as it should, and when you add new music or videos to iTunes, they will be stored on your external drive along with all the others. However, if you've got computer-OCD like me, you'll want to move all those other iTunes files that I just mentioned too.
Make sure iTunes isn't running, and then go to your original iTunes folder location, and there will be those few files (iTunes Library.itl, iTunes Music Library.xml, iTunes Library Genius.itdb etc) and folders (Previous iTunes Libraries, Album Artwork etc) in there. You can copy and paste these into the root of your new iTunes drive (i.e. NOT in the iTunes Media folder) and then, once this is done, you ned to start up iTunes whilst holding down the option key on a Mac, or shift key on a PC, and iTunes will ask you to choose an iTunes library. Click "Choose library" and navigate to your new drive and click OK. iTunes will start up, and from hereon will remember where to find its files. You can delete the original files once everything is working correctly, or if you're paranoid like me, you can back them up safely in a separate folder somewhere else in case of disaster.
All of this will mean that you've moved all of iTunes, wholesale, to your new external drive.
By default, Time Machine WON'T be backing up this new drive at this point, so make sure you go to the Time Machine preferences and remove your iTunes drive from the "Exclude" list under the "options" menu. The next time Time Machine works its magic, it'll backup not only your internal drive but also your external iTunes drive as well. Sorted.
