I don't know that the restore process is really that different for virtual servers as compared to a physical box. What really drives the process itself is going to be how you back up the virtual machines (VMs) or physical box. The major difference between the two would be if we were looking at an imaging backup alone and we were doing all of our backups with only VM images. In those cases, the restore process can be a little different.
In a traditional restore process, with the agents being inside the guest, nothing is really going to change.
Let's assume that you have a complete system meltdown and you have to do a complete restore of a system. You would do the same thing on the VM side as you would on the physical side; reinstall the operating system, put an agent back on, do a system restore and include all of the system volume. You can speed up the process because instead of doing a physical installation of the hardware, you can deploy a new VM template and know that all of the hardware drivers are going to match and simplify it.
For an image process, the image restore is pretty simple. It depends on the tool you use, but in almost all cases, you can pretty much pick out the image, point to the volume that you wish to restore it and allow it to do its data transfer and to copy the data. Most software will reregister the VM that was dumped into the host operating system to start the VM up. You will then have essentially a point-in-time image of the VM from whenever that snapshot or image was taken.
Some people will combine the two. I used to take images every Saturday of my primary VMs and then I would run normal agent-based backups during the week. If I had to restore, I wouldn't bother with building a new VM. I would actually restore the original image knowing I had the right OS, the right name and that everything was already preset. And then I would restore the data from the traditional backup. So it will vary a little, but for the most part not change all that much.
In terms of recovery, it can be business as usual for restore. When you look at bare-metal recovery, another big change here is that most SMB shops will have some form of bare-metal recovery, probably in terms of reloading the operating system and reloading the agent, and then reinstalling the data using the backup software in place.
But outside of those two approaches, SMBs are rarely using other third-party products that are integrated with software for image-based restores. In fact, image-based restores, when you look at how that happens in a traditional backup environment, are not commonly deployed for bare-metal or full-system recovery because of the time it takes. It's more used a remedy for machines with millions of files that take too long to backup via traditional methods. The opportunities via VMware Consolidated Backup (VCB), snapshots, etc., open the door for better ways to do full system recovery using images.
This was first published in June 2008