iMovie (or iPhoto) and disk full

I'm new in this forum, so first: Hi to all!

Yesterday I was working with my friend with his Mac on iMovie. He has the disk pretty full of media so he's reaching the upper disk's limit.

My question is: what is going to happen to the media library when the disk will be full. I mean: can the library be splitted over 2 different disks?
The advantage is to have all centralized: music, photos and movies.
What will happen?

Thanks in advance and regards.

yes you can span 2 discs with media.... generally speaking you don't want to span a movie over 2 discs tho

Thanks a lot!