Q: I already have iTunes match, with the home library on my macbook. I use a work MacBook, plus iPad and iPhone to access via iCloud. As the library is taking up so much space on my computer, I want to move it to an external hard drive. If I do this, will iTunes match still work – both on my home computer and other devices?

– Ren
A: Moving your library with iTunes Match enabled won’t be a problem at all, and in fact the process is exactly the same whether you’re using iTunes Match or not—see our guide to Transferring your iTunes Library for more information.
The iTunes Match service works at the library database level, so it uses the information that’s already in iTunes to track your actual file locations. However, once the actual matching and uploading process is completed, you don’t technically even need to keep the actual files in your library, since you can stream or download them from iCloud to your original computer in the same way as you would for any of your other computers.
It is recommended that you keep a backup of your library somewhere, and if you’re using an external hard drive it’s usually just as easy to move your files there and keep them in your library. However, you could also just transfer your files to offline storage for backup purposes and then delete them from within iTunes. With iTunes Match enabled, you’re given the option when deleting a track to remove it only from your current iTunes library or remove it from iCloud; with the also delete this song from iCloud box Unchecked, the track will remain accessible in your iTunes library for streaming or you can re-download the matched version from iCloud at any time. For matched tracks this method can also be used to replace older, lower bit-rate tracks with the 256kbps iTunes Store versions.
Keeping the actual files in your library will of course be necessary if you’re still syncing music directly over USB or Wi-Fi to an iOS device or a traditional iPod model, or if you need to have access to your entire music library even when not connected to the Internet.