On Fri, Nov 21, 2014 at 4:01 PM, Markus Stockhausen <stockhausen@collogia.de> wrote:
Hi Gianluca,

it took me some time to correct my misunderstanding. I advised to update
only libvirt as I was aware of the (old) block-commit command of qemu. 
With that you can merge snapshots in the chain (history) but not into the 
active layer (the current running state). Merging data into the active
layer needs active-commit that is available since qemu 2.0 . That explains 
the error you got.

OVirt makes use of the second scenario so no luck without a full installation
of virt-preview repos or a jump towards FC21.

Markus


it seems not so...
In my F20 oVirt 3.5 All-In-One with libvirt-1.2.9.1-1.fc20.x86_64 and qemu-1.6.2-10.fc20.x86_64 I have:

Situation on a C7 VM

Date                       Status   Description
Current                   OK        Active VM
2014-Nov-23, 12:01 OK        one_after_first
2014-Nov-21, 00:54 OK        test per live merge


- Trying to delete "one_after_first"

Thread-13::DEBUG::2014-11-23 12:04:15,782::libvirtconnection::143::root::(wrapper) Unknown libvirterror: ecode: 67 edom: 10 l
evel: 2 message: unsupported configuration: active commit not supported with this QEMU binary
Thread-13::ERROR::2014-11-23 12:04:15,783::vm::5751::vm.Vm::(merge) vmId=`0ba6a56b-542c-480e-8bab-88aea9195302`::Live merge f
ailed (job: 10c6aed1-3f03-439a-b037-e1b6c55ecada)
Traceback (most recent call last):
  File "/usr/share/vdsm/virt/vm.py", line 5747, in merge
    flags)
  File "/usr/share/vdsm/virt/vm.py", line 670, in f
    ret = attr(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/vdsm/libvirtconnection.py", line 111, in wrapper
    ret = f(*args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/libvirt.py", line 638, in blockCommit
    if ret == -1: raise libvirtError ('virDomainBlockCommit() failed', dom=self)
libvirtError: unsupported configuration: active commit not supported with this QEMU binary

- Trying to delete "test per live merge"
Thread-13::DEBUG::2014-11-23 12:10:35,901::libvirtconnection::143::root::(wrapper) Unknown libvirterror: ecode: 67 edom: 10 l
evel: 2 message: unsupported configuration: this qemu doesn't support relative blockpull
Thread-13::ERROR::2014-11-23 12:10:35,902::vm::5751::vm.Vm::(merge) vmId=`0ba6a56b-542c-480e-8bab-88aea9195302`::Live merge f
ailed (job: e0433ad1-cb2c-4b09-b2fc-9c9d4e513957)
Traceback (most recent call last):
  File "/usr/share/vdsm/virt/vm.py", line 5747, in merge
    flags)
  File "/usr/share/vdsm/virt/vm.py", line 670, in f
    ret = attr(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/vdsm/libvirtconnection.py", line 111, in wrapper
    ret = f(*args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/libvirt.py", line 638, in blockCommit
    if ret == -1: raise libvirtError ('virDomainBlockCommit() failed', dom=self)
libvirtError: unsupported configuration: this qemu doesn't support relative blockpull