The amount of capacity, just because of what's being backed up has increased significantly. We just conducted a survey of people who have recently adopted server virtualization, and 37% say that the amount of data they back up increased after deploying server virtualization. It's significant. You're backing up the operating system, you're backing up applications, and you're backing up data.
Then, there is the proliferation of virtual machines or VM sprawl. Once you get the infrastructure set up and in place, actually deploying the virtual machine is pretty simple. It's really just a matter of clicking a couple of buttons, and you have a new machine set up. But after you do that, is the proper backup process in place?
So, there's more data to be backed up and there's more virtual machines, but you still have to back up the data within the same window. It's important to be aware of that.
Check out the entire Virtual server backup FAQ