[libvirt-users] Fwd: Connecting disks to controller virtio-scsi of qemu/kvm

[chickenmarkus at freenet.de]

Hello,

in another mail list with another issue I had problems with HTML 
content. Due no response I send my question in PLAIN/TEXT again.

Bye Markus


-------- Original-Nachricht --------
Betreff: 	Connecting disks to controller virtio-scsi of qemu/kvm
Datum: 	Wed, 05 Feb 2014 18:37:06 +0100
Von: 	chickenmarkus at freenet.de
An: 	libvirt-users at redhat.com



Hello,

I try to use the virtio-scsi driver to use my disks. But my setup at first:

  * in general Debian Wheezy
  * Kernel: 3.11-0.bpo.2-amd64
    (http://packages.debian.org/wheezy-backports/linux-image-3.11-0.bpo.2-amd64)
  * Qemu-KVM: 1.7.0 (http://packages.debian.org/jessie/qemu-kvm)
  * Virsh 1.2.1 (http://packages.debian.org/jessie/libvirt-bin)

The new kernel and dirty things from Jessie are for discard support 
(also not working with current configuration despite thin volumes with 
working discard). Once I have the this "new" qemu version, why not to 
use virtio...

Every disk with target bus "scsi" gets an own scsi-hd device. Libvirt 
ignores the scsi controller of type virtio-scsi.
Here is a XML snippet:

    <devices>
    <controller type='scsi' model='virtio-scsi' index="0"/>
    <disk type="block" device="disk">
         <source dev="/dev/ssd0/sarabi"/>
         <driver discard="unmap"/>
         <target dev="sda" bus="scsi"/>
         <address type="drive" controller="0" bus=0/>
    </disk>
    </devices>

This creates the virtio-scsi controller (verified by lspci in guest) but 
do not "connect" the disks to it. The resulting command line looks 
following:

    kvm [...] -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x5 -drive
    file=/dev/ssd0/sarabi,if=none,id=drive-scsi0-0-0-0,format=raw,discard=unmap
    -device
    scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=2
    [...]


How get my disk to run over virtio-scsi? Or did I found something like a 
bug?

Bye Markus