[Users] EL5 support for VirtIO SCSI?

[Stefan Hajnoczi]

On Thu, Nov 14, 2013 at 02:39:33AM -0500, Ayal Baron wrote:
> > ----- Original Message -----
> > > Hello Itamar.
> > > The specific use case is a particular propriety filesystem that needs to
> > > see
> > > a scsi device. It will do scsi inquiry conmmands to verify suitability.
> > > In talking to the devs - of the filesystem - there is no way around it. I'd
> > > previously tried virtio-block - resulting in the /dev/vd* device - and the
> > > filesystem would not work.
> > > 
> > > From doing a bit of web searching it appears the kvm/qemu supports (or did
> > > support) an emulated LSI scsi controller. My understanding is that the
> > > various virtualization platforms will emulate a well supported device (by
> > > the guest OSes) so that drivers are not an issue. For example this should
> > > allow a VM on Vmware vsphere/vcenter to be exported to Ovirt and have it
> > > boot up. The potential for further optimising the guest is there by
> > > installing ovirt/qemu/kvm guest utils that then allow the guest OS to
> > > understand the virtio nic and scsi devices. The guest could then be shut
> > > down, the nic and scsi controller changed and the guest booted up again.
> > > You can do the same thing in the Vmware world by installing their guest
> > > tools, shutting down the guest VM, then reconfiguring it with a vmxnet3 nic
> > > and pvscsi scsi adapter, then booting up again.
> > > It does seem somewhat inconsistent in Ovirt that we allow a choice of Intel
> > > e1000 or virtio nics, but do not offer any choice with the scsi adapter.
> > 
> > virtio-scsi support was just recently added to oVirt to allow for scsi
> > passthrough and improved performance over virtio-blk.
> > I believe the emulated scsi device in qemu never matured enough but possibly
> > Stefan (cc'd) can correct me here.

The only supported emulated SCSI HBA device is virtio-scsi.  It was Tech
Preview in RHEL 6.3 and became fully supported in RHEL 6.4.  virtio-scsi
is not available in RHEL 5.

Stefan