[libvirt-users] Proper way to reference a disk

[Michael Schwager]

Hi,
We are running on CentOS 7.0. We want to move our VMs (kvm/qemu) from
qcow/image files to logical volumes under LVM.

I have moved one of them but I had a little trouble editing the disk
properly and I wonder what is the correct way to do it. Specifically, in
the XML under the devices/disk section why does the source say "source file=",
and not "source dev="?  The reason I ask is that I have a number of other
machines to move and I don't want to mess them up.

The source file entry for the disk was like this in our xml file:
<source file='/var/lib/libvirt/images/pxetest.qcow2'/>

I got the vm to work by converting the image to raw, then dumping via dd
into the LV, and editing the XML using virsh as follows:
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='none'/>
      <*source file*='/dev/kvm_temp/pxetest'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
function='0x0'/>
    </disk>

By comparison I have a test machine on another real host upon which I
loaded a VM and put its disk into a logical volume. Its disk section looks
like this:

    <disk type='block' device='disk'>
      <driver name='qemu' type='raw' cache='none' io='native'/>
      <*source dev*='/dev/kvm_hosts/pxetest2'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>

The source file / source dev thing really has me wondering.


*- Mike Schwager*

*  Linux Network Engineer, Mocho Trading LLC*

-- 
This message is for the named person(s) use only. It may contain 
confidential proprietary or legally privileged information. No 
confidentiality or privilege is waived or lost by any mistransmission. If 
you receive this message in error, please immediately delete it and all 
copies of it from your system, destroy any hard copies of it and notify the 
sender. You must not, directly or indirectly use, disclose, distribute, 
print, or copy any part of this message if you are not the intended 
recipient. Mocho Trading LLC reserves the right to monitor all e-mail 
communications through its networks. Any views expressed in this message 
are those of the individual sender, except where the message states 
otherwise and the sender is authorized to state them to be the views of any 
such entity.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/libvirt-users/attachments/20150506/33dc4abf/attachment.htm>