After reviewing a brief article which asks more questions that it answers over at techtarget. “The best way to back up a virtual machine” I really thought about how a medium to large company does backups on their physical network and realized that virtual machines shouldn’t be any different. But there are more options with virtual machines, because of the management consoles associated with them. Having worked in an environment where I had to run weekly tape backups I know that you generally don’t back up the whole machine each week. The Data is the value, not the OS. Why are people thinking they want to fill up their backup tape servers with complete virtual images? Because they are lazy.

For people who don’t remember the early days of computing, when things where simple. You had a floppy disk with your program and operating system, and a second floppy disk with your data. You could share your data disk and keep your software at home. Then came hard drives, and people would do partitions, and have the operating system, the applications, and the data on 3 separate partitions, or if lucky separate drives. Now why are people thinking it is good policy to forget the past and put the data with the vulnerable operating system?

How would I go about setting up a medium sized redundant virtual farm? Glad you asked, here is my thoughts.

If you are in a heavy data server farm, then you should have your data in an isolated enclosure, which the backup server can access directly, and the virtual machines can also access.

If you are in a heavy processing needs, then you may want use images to create the virtual machines for a clustered or load sharing environment, so when you make changes to your machines you can deploy the new images quickly and easily. Ever consider using Subversion with Virtual Machines? Every time you deploy a new image, just save a version. New image doesn’t work, just go back a version.

For smaller business, the one thing I would recommend avoiding is using a backup agent to talk to the virtual machine guest os. This just plain doesn’t make sense. The amount of overhead being used to talk to the guest os, request files and perform the backup just don’t seem practical. There are a few exceptions to this, and that would be something like a e-mail server or small database server where having the data in a san or nas isn’t practical for a smaller company.

Warning, Never try to back up any running virtual machine. All reports show that it is best to stop the machine to have complete safe file access.

Sources:
How to back up virtual machines in Virtual Server 2005
Backing up and restoring Virtual Server
Backing Up Virtual Machines and the GSX Server Host
Backing Up the Virtual Machine
Asigra Targets Virtualization with its 64-bit Software
Why Run VMware Over NAS?