I may have stumbled across a virt-v2v bug. 

I just did a successful virt-v2v migration of a Windows 2008 server from an ESXi host to a RHEV environment.   While the VM was still on the ESXi side, I removed its VMWare tools and rebooted it just make sure it was still functional.  Then I shut it down and V2V’d and imported it into RHEV. 

When I first powered up the new RHEV copy, it found and installed the driver for the Virtio NIC and tried to install the Viostor SCSI driver, but failed with “Access Denied”.  This was strange.  Looking at the Windows Device Manager, I noticed a SCSI controller without any driver and an “Unknown Device”.  This looked similar to the situation when it was an ESXi VM. 

I tinkered around with drivers a little bit, trying to be the Viostor stuff to load.  It never did.  So I rebooted the VM, just to make sure it would come back up while I was there to watch it and I could deal with its missing 2^nd disk drive later.  Good call – it went into a crash/reboot loop.  Bummer.

I caught it and tried “Last Known Good” from the Windows boot menu.  This never works, but I keep trying anyway.  Good thing, because this time it came right back up.  It also successfully loaded the Viostor block driver this time and now there are no more SCSI controllers without drivers and no more Unidentified Devices.  And that VM’s second hard drive also showed up – this was probably the “unknown device” from before. 

I wonder if virt-v2v wrote its registry updates to the wrong registry control set and I stumbled across it? 

And a tip for anyone else – if your Windows VM crashes after a virt-v2v, try booting with Last Known Good.

- Greg Scott