Question about moving kvm instances with several volumes

Here's a question (didn't find a clear answer in the doc) :

We would like to add a second volume to some of our KVM instances. If we do so and then want to move those instances from a KVM host to another, will BOTH volumes be recreated on the new host ? Or will we have to do some manual work ?

That's a important question, as we have to choose between expanding actual volumes or creating new volumes (we have some dirs with an increasing volume of data : putting those dirs in another volume would avoid the risk of getting the root filesystem full).

Thanks a lot.