Geek stuff: How to backup iPhone to external hard drive via iTunes on MacBook

I've been having problems with backing up my iPhone (and iPad) via iTunes on my MacBook Air because I don't have enough space on my hard drive. So I thought, "hey, why don't I do the iPhone backup to my giant external hard drive instead?". To achieve this I had to create a symbolic link (or symlink). This is a special type of file that contains a reference to another file or directory in the form of an absolute or relative path and that affects pathname resolution. A symbolic link contains a text string that is automatically interpreted and followed by the operating system as a path to another file or directory. This other file or directory is called the "target". The symbolic link is a second file that exists independently of its target. BTW, I got all that info and description about symbolic links from wikipedia, so if you want to know more then click here.

Step 1

Firstly you need to create your destination folder on your external hard drive. I just set up a folder structure: MobileSync/Backup

Step 2

Remove the existing backup folder (I am assuming you've got necessary copy of your iPhone backups stored elsewhere). You can’t create a symlink file if another file in that directory has the same name.

The existing backup folder is located at: ~/Library/Application Support/MobileSync/Backup/

From the Mac OS X Finder, hit Command+Shift+G to bring up the “Go To” window, type the following directory in:
~/Library/Application Support/MobileSync/

I'm switching to the terminal at this point and deleting using the command line:
sudo rm -rf ~/Library/Application\ Support/MobileSync/Backup/

You will be prompted for your password.

Step 3

Now we'll create the symbolic link and set the target location. My external hard drive is called ExternalHDD. You will need to replace that with the name of your drive.

ln -s /Volumes/ExternalHDD/MobileSync/Backup/ ~/Library/Application\ Support/MobileSync/Backup

After the symlink is in place, any browser (or other application) that tries to write to ~/Library/Application Support/MobileSync/Backup/ will actually save the file to the linked location on the hard drive.

Did you find this information useful? I'd love to hear your feedback, so please leave a comment if this post was helpful to you.

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