Problem/Justification
We can only currently use virtio-blk and AHCI for our storage devices in VM but virtio-scsi is a more modern driver and also alows different configurations.
we should keep virtio-blk
Some Research
Proxmox recommends using SCSI with VirtIO SCSI single as SCSI Controller Type for VM disks, to have the most features and best performance.
VirtIO block may get deprecated in the future.
Looking at the advantages of virtio-scsi, I believe it’s the correct choice as a default VM disk interface in oVirt. For optimized VMs, there is always the choice of manually switching to virtio-blk (or IDE, if you’re optimizing for slowness… or compatibility).
Impact
TrueNAS emulation platform is well behind current norms.
yeah virtio-scsi would be nice on scale. ui only gives virtio-blk / ahci right now.
for windows guests virtio-scsi single is usually the better path (multi queue, discard, etc). linux guests are fine on virtio-blk for plain disks, scsi helps more when you want multiple disks / cdrom on one controller.
+1 on exposing it in the vm disk device picker. till then people hack libvirt xml / midclt device create and it gets messy on upgrades.
Discard/unmap has been added to virtio-blk a while back, but I do get the impression it is now the legacy driver, a bit like AHCI which is just a modified IDE driver and all the limitations that comes with.
