My incredibly quick take on FastScale is that it allows you to dedup at build time. Before you deploy anything you pull the duplicate data out of the operating system images before they're even built. It never touches disk as it was never there in the first place.
You're not going to deploy VDI or a Private Cloud using multiple guest operating systems, you're going to do with Just enough OS (JeOS) while dumping unnecessary software components and libraries as you deploy the image files.
If something requests a component you've stripped out it and it's dependencies will be dynamically loaded from a centralised repository of components and away you go.
This is capacity optimisation before deployment. Deduplication at installation.
