VMWare Server backups

[emulator]

Hi All...

 

We are backing up some virtualized servers, and I thought that I'd pass along how we are doing this. I added the following in our backup procedures manual. I hope that this helps others:

 

The process of backing up virtual servers is slightly different than backing up normal servers. Virtual servers do not run from normal hard drive partitions, but instead run from virtual hard disk image files. These files are large, and do not support normal backups.

 

Consider the following example. A virtual, expanding hard disk image file of 50gb is backed up by Retrospect. The virtualized server then makes a change to its virtualized “hard drive†by writing a 100mb file to its desktop. To the virtualized server, the hard drive capacity has changed by only 100mb. However, from Retrospect’s point of view, the entire virtual hard disk image file has completely changed. This means that the disk image file must be backed up again, in its entirety. The backup takes another 50gb plus 100mb, as the disk image has grown by 100mb. Doing daily backups in this way requires a large backup media capacity.

 

Note: compression does reduce the amount of storage required.

 

To solve this capacity issue, we install the Retrospect backup client on the virtual server host and on the virtual server guest operating systems. We back up the virtual disk image files once per week, and then back up the guest OS as if it is a real server daily. Backing up the virtual server as if it is a real server backs up only the changes to the virtual disk file.