For datacenters, clustering of machines ( minimum of two ) which is already in place for disaster recovery will take care of this. For the home user it still will rely on backups and how often your routine is. Doesn't present any more risk just consolidates a lot.
The "of" should have been "or". Sorry for the typo.
Consider this - each virtual platform will have it's own IP address. You can restrict traffic based upon what each virtual server is doing and lock it down. A print server doesn't need web services, a database doesn't need file and print sharing, etc. You reduce the amount of traffic and security holes on each server. Compare that to a single server which is doing all of those things -- it is handling way more traffic and well as way more open ports than any one of your virtual machines. And consider this - one of your machines goes down - if you've put all of your eggs in one basket as it were, you lose all of that. Where as if you lose one virtual machine, the others are still running. Plus , I have less hardware and maintenance costs with the VM's, because it's one hardware machine.
There are other issues as far as ease of backup and restore but I will stop here. Thanks.
I took a look into this virtualization concept and found that its main benefit is for user to run more than 1 OS on the same PC concurrently. This will allow, for example, someone to run linux as a guest OS if that's the only way to run a specific Apps not available on the main OS.
In a datacenter, it would appear to me that once an OS has been chosen, it will be the OS running on all its machines. It is rare to require an guest OS since the main OS was chosen well ahead based on the kinds of Apps.