Storage virtualization is a very strategic decision for a company to make. Be conscious of what you're doing, because reversing virtualization is not easy. Once you go into a virtualized environment, the relationship between what is being presented as storage to the server and where that physical storage is coming from is completely abstracted -- an IT storage administrator won't know where storage is coming from. You will probably live with a vendor's storage virtualization product for years to come, so it is absolutely crucial to pick your vendor carefully.
You can back out of storage virtualization, but it's a painful project. You'll basically have to backup your data...
somewhere else, remove the virtualization layer, then bring the data back onto known physical storage devices. It's not a course to be undertaken lightly.
Check out the entire Storage Virtualization FAQ guide.