I recently turned an old gaming computer into a server and decided to put XenServer 7.5 on so I could flip between Windows and Linux servers. Installation of the hypervisor went well and I proceeded to setup a Windows 10 virtual machine. I installed some basic programs, then shut it down for the night.
I removed the Windows installation disk before shutting the server down, thinking I was done with it.
When I tried to start the VM later, I got the error message -
Unable to attach empty optical drive to VM.
The VM failed to start. I thought that it was a Windows issue and spent a full day attempting to debug it by reinstalling Windows and setting up a second VM to try and reinstall properly.
Last night I tried to do the same thing with a Fedora Linux disk I had lying around. OS setup went well. Remove installation disk, then the VM won't boot.
Both VMs boot fine when I still have the installation disks in, and changes are saved between sessions.
In addition, trying to start the VMs from the server console gives the error:
Failed: SR_BACKEND_FAILURE_456
TL;DR: VMs on my XenServer won't boot without their original installation media.
