My company has tried VMware VCB with very mixed results which is not good for a backup solution. When we tried to restore some vms, they appeared as they had crashed. In talking with VMware support they acknowledge this is "an issue" that they're working on.
I don't know what that means, but that's unacceptable for any backup solution.
We've seen that Windows 2008 hyperv has a live backup feature that somehow integrates with vss. This could be the perfect solution if it works. Any news on that?
And this article attempts to cover the backup dilemma in the Virtual World:
Traditional backup systems have a one-to-one relationship with servers. These tried-and-true backup systems and associated software already support storage-area networks (SAN), fiber optics, and the latest operating system and server hardware updates. But they are not geared specifically for the complex world of virtualization, which involves multiple guest operating systems on the same box.
Dave Russell, Gartner Inc.'s vice president of research for servers and storage, outlined three popular strategies for virtualization backups. The most common is putting software agents on each virtual machine (VM) and then using traditional enterprise backup software. A second approach is to create an image of the VM and either use a storage service hosted elsewhere or take daily snapshots of the logical unit number (LUN).