"Virtual Machines (VMs), often nearing the 100GB mark
in size, are too large for traditional media, too large for quick
transport via Internet lines and can't be disconnected and
physically carried from one location to another.
"Let's say that you've signed-up with a hosting service who'll
host your virtual infrastructure for you and you've built two dozen
or so virtual machines in that environment. After several painful
months of service, you decide to discontinue your service with that
vendor and move to a different service -- now what? How do you move
your virtual machines? Do you move them at all or just delete them
and start from scratch with the new vendor? Let's examine this and
other options available to you."