Xubuntu VM wont boot with virtio scsi.

[potetpro]

Hi.
Does some distros not have the virtio scsi module?
After installing Xubuntu 18.04 in a VM, it told me I/O error as it was about to reboot, then just hanging after boot.
If i change the HDD controller to scsi single, it boots just fine. But as i read in the wiki scsi single does not support backup.

 

[dcsapak]

what exactly did you change? scsihw from 'virtio-scsi' to 'virtio-scsi-single' ? if yes this is the same hardware only the disks are connected differently (up to 6 or 7/ controler vs 1/controller)

 

[potetpro]

Ok, so this is strange.
When video is set to default, it looks like it does not use SPICE (xubuntu uses xfce, dont know if that has something to do with it).
When i use VirtIO scsi it wont boot, if i change the disk to IO-Thread, it boots (???)
If i change the display to spice, it boot either way, with IO-Thread or without. Strange