[ovirt-users] Re: Terrible Disk Performance on Windows 10 VM

You found the issue! VirtIOSCSI can only do its magic, when it's actually used. And once the boot disks was running using AHCI emulation it's a little hard to make it "re-attach" to SCSI. I am pretty sure it could be done, like you could make Windows disks switch from IDE to SATA/AHCI with a bit of twiddling in the registry using recovery mode. I think I managed to feed the Windows installer a floppy image with the VirtIO drivers at one point, but it took me half a workday I think... That is one of the reasons I like importing my Windows VMs for oVirt from VirtualBox. And it doesn't seem to like the OVAs VMware produces.