[Users] EL5 support for VirtIO SCSI?

[Itamar Heim]

On 11/14/2013 09:09 AM, Paul Jansen wrote:
> Hello Stefan.
> Thanks.  I understand qemu supports other scsi adapters however.  See
> this
> <https://www.redhat.com/archives/libvir-list/2013-March/msg01254.html>
> 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?

hooks are compatible with the ui. you'd define a custom property with 
scsi=xxx or something like that.
see for more detials:
http://www.ovirt.org/VDSM-Hooks

>
> 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.
>
>
> Stefan
>
>