Hi,
I recently upgraded to 4.1.0 from 4.0.2 and during the upgrade, a single VM somehow got corrupted and would no longer boot (probably a comedy of errors all mine). I decided rather than solving the VM's filesystem problem, I could just restore this VM from backups and save the time and trouble. Then I went to do it and learned the hard way that VirtualBox apparently can't be treated this way.
My backups are host filesystem backups made nightly with Amanda, and the VM in question has a single disk image file in /opt/virtualbox-instances/<hostname>. There also was a snapshot stored in /root/.VirtualBox/Machines/<hostname>/Snapshots. I have copied these back into place and no-go, VirtualBox caused a kernel fault when I tried to run this VM. I have tried creating a new VM with identical settings and using the disk image file, and this works - but the snapshot data contains valuable configuration changes and so forth, which are not incorporated into the VM. I think at a minimum I should be able to merge the base image + snapshots but since I can't run the VM and VirtualBox now doesn't know offically about the snapshot, there's no command line way to accomplish this.
This problem defeats completely my backup strategy since I was depending on being able to restore virtual machines singly. By making Virtualbox so interdependent, I can't seem to just 'have a problem' with a single vm image, it would seem that I would have to restore my entire host filesystem (rolledback to the older virtualbox too) in order to get this one thing back.
I would like input on any strategy I might use in the future to allow me to be able to restore single vm's. Adding a backup client to each VM may work but it would be so much easier to just get the host that it begs the question. Ideally I want to divorce completely the storage of my VM's from the running of the VM's, which would place the images on NFS for example, so maybe I can launch vm's for failed hosts on other hosts for example, so this is going to become more important to me.
Thank you.