[Users] EL5 support for VirtIO SCSI?

Paul Jansen vlaero at yahoo.com.au
Thu Nov 14 14:09:13 UTC 2013

Hello Stefan.
Thanks.  I understand qemu supports other scsi adapters however.  See this post from earlier this year.
That post makes reference to the following hbas: auto, buslogic, ibmvscsi. lsilogic, lsisas1068, lsisas1078, virtio-scsi, vmpvscsi.
The post is referring to libvirt, so the number of adapters may be related to the various virtualization backends that libvirt can interface with.

There are numerous references to qemu/qemu-kvm supporting other scsi adapters as well as AHCI SATA.  I installed the Centos 6.4 based node, so perhaps the Fedora 19 based node has a newer qemu that supports more of these features?  I might see if I can do an install of the Fedora 19 based node tomorrow.

Ayal mentioned using 'hooks' to interface with qemu to possibly create a VM outside of the definitions that Ovirt allows.  If I am understanding this correctly - how do I do this?  Am I to expect some interface inconsistencies in the ovirt portal I I view a 'custom' VM like this?

So, in short - is there the potential for me to create a VM in ovirt that has a SCSI/SAS/SATA HBA and attach disk(s) to it (other than the virtio-scsi HBA which is not supported under EL5)?

On Thursday, 14 November 2013 11:22 PM, Stefan Hajnoczi <stefanha at redhat.com> wrote:
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.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ovirt.org/pipermail/users/attachments/20131114/2421e9b7/attachment-0001.html>

More information about the Users mailing list