I'm struggling to understand how to do differencing disks in VirtualBox v3.1.0. I've created a Windows 2008 Server, but now I want to use that as a base image for a number of other servers. The help file has a description of what differencing disks are, but I can't find where it actually tells you how to do it. In the Storage dialog for a server I found the Differencing Disks checkbox: alt text http://www.philippursglove.com/stackoverflow/virtualbox%20differencing%20disks.png but when I check it, I'd expect it to then ask which image should be the parent so I could select my base image.
Any pointers you can offer would be greatly appreciated!
Disconnect and remove VHD from VirtualBox and then register it with a command line:
VBoxManage openmedium disk -type immutable
After you attach it to a virtual machine, VirtualBox will automaticly create a differencing disk.
Now it beats me, how to create a chained differncing disk from that one?, To have for eg. W2008 -> W2008+SQL2008 -> W2008+SQL2008+SharePoint?