VirtIO SCSI is a new para-virtualized SCSI controller device for KVM instances. It has been designed to replace virtio-blk, increase it's performance and improve scalability. The interface is capable of handling multiple block devices per virtual SCSI adapter, keeps the standard scsi device naming in the guests (e.x /dev/sda) and support SCSI devices passthrough.
The SCSI controller model can be set to virtio-scsi by proving the hw_disk_bus_model=virtio-scsi property in Glance image metadata. Otherwise, libvirt will automatically configure it's default model.
glance image-update \ --property hw_scsi_model=virtio-scsi \ [image]
All virtual devices which has it's bus set to "scsi" will be tied to this controller. Currently the following properties can be set to scsi, together with the hw_scsi_model: hw_cdrom_bus hw_disk_bus hw_floppy_bus