[ovirt-users] Using Virtio-SCSI passthough on SCSI - Devices

[Itamar Heim]

On 04/28/2014 03:54 AM, Jeremiah Jahn wrote:
> looks like libvirt should be able to do it with it's hostdev entries.
>
> http://libvirt.org/formatdomain.html#elementsHostDevSubsys
>
> <devices>
>      <hostdev mode='subsystem' type='scsi'>
>        <source>
>          <adapter name='scsi_host0'/>
>          <address type='scsi' bus='0' target='0' unit='0'/>
>        </source>
>        <readonly/>
>        <address type='drive' controller='0' bus='0' target='0' unit='0'/>
>      </hostdev>
>    </devices>
>    ...

so i think 'hostusb' would be a very good match for a custom hook:
http://www.ovirt.org/VDSM-Hooks
http://www.ovirt.org/VDSM-Hooks_Catalogue
http://gerrit.ovirt.org/gitweb?p=vdsm.git;a=tree;f=vdsm_hooks;


>
> On Sat, Apr 26, 2014 at 4:09 AM, Itamar Heim <iheim at redhat.com> wrote:
>> On 04/25/2014 08:01 PM, Daniel Helgenberger wrote:
>>>
>>>
>>> On Fr, 2014-04-25 at 17:19 +0200, Jiri Belka wrote:
>>>>
>>>> On Fri, 25 Apr 2014 13:40:09 +0000
>>>> Daniel Helgenberger <daniel.helgenberger at m-box.de> wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> does anyone have an idea on how to accomplish this? In my particular
>>>>> setup, I need a FC tape drive passed though to the vm.
>>>>> Note, passing throuh FC - LUNs works flawlessly.
>>>>>
>>>>> If I understood Virtio -SCSI correctly, this should be possible from
>>>>> libvirt's part.
>>>>
>>>>
>>>> I can be wrong but my understanding is that dm-mpio works on block
>>>> layer thus it does not support multipath for tapes/cd-devices.
>>>>
>>>> But I could be wrong, I got this info from an OpenBSD paper comparing
>>>> SCSI multipath implementation.
>>>>
>>>> j.
>>>
>>> No, I think so too - it does not support tape drive as such (but I could
>>> set up a tape library as a LUN to use it with LTFS for instance)
>>>
>>> The point being is another. VirtIO SCSI should be able to pass through
>>> any scsi device; like tape drives end enclosures. I know this works in
>>> Proxmox: http://pve.proxmox.com/wiki/Tape_Drives
>>>
>>> Does it work in oVirt, too? In the GUI I only see block LUNs from DM.
>>
>>
>> i suggest you try making it work via libivrt first, then we can compare to
>> the xml passed to the guest, workaround with a custom hook, etc.
>>
>>
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