In general, in order to delete a disk while it is attached to a running VM, the disk has to be deactivated (hotunplugged) first so it won't be accessible for read and write from the VM.
In the 'edit' VM prompt there is no option to deactivate the disk, it should be done from the disks subtab under the virtual machine.

On Tue, Dec 13, 2016 at 5:33 PM, cmc <iucounu@gmail.com> wrote:
Actually, I just tried to create a new disk via the 'Edit' menu once
I'd deleted it from the 'Disks' tab, and it threw an exception.

Attached is the console log.

On Tue, Dec 13, 2016 at 3:24 PM, cmc <iucounu@gmail.com> wrote:
> Hi Elad,
>
> I was trying to delete the disk via the 'edit' menu, but noticed just
> now that there was a 'disks' tab when the machine was highlighted.
> This has a 'activate/deactivate' function, and once deactivated, was
> able to remove it without error.
>
> It does offer the option of deleting the disk when right clicking on
> the VM and choosing 'edit', however, there is no 'deactivate' option.
> Not sure if this is by design (so that users should look elsewhere). I
> can still try to run the delete from the 'Edit' page, and capture
> browser console output. Otherwise, apologies for troubling you with
> this.
>
> Kind regards,
>
> Cam
>
> On Tue, Dec 13, 2016 at 12:27 PM, Elad Ben Aharon <ebenahar@redhat.com> wrote:
>> There is no indication for image deletion in engine.log
>> The browser console log is located in your browser under
>> 'settings'->'developer'.
>> Please try to delete a disk as you tried before, get the console log and
>> provide it.
>>
>> Thanks
>>
>> On Mon, Dec 12, 2016 at 7:40 PM, cmc <iucounu@gmail.com> wrote:
>>>
>>> Hi Eled,
>>>
>>> I've attached the ui log and the engine log but I'm not sure what the
>>> browser console log is - there is a 'console.log' in
>>> /var/log/ovirt-engine,
>>> but it is zero size (do I have to turn up debugging perhaps?).
>>>
>>> Kind regards,
>>>
>>> Cam
>>>
>>> On Sun, Dec 11, 2016 at 2:26 PM, Elad Ben Aharon <ebenahar@redhat.com>
>>> wrote:
>>> > Hi,
>>> >
>>> > Please attach browser console log and engine.log
>>> >
>>> > Thanks
>>> >
>>> > On Fri, Dec 9, 2016 at 8:04 PM, cmc <iucounu@gmail.com> wrote:
>>> >>
>>> >> Just another note on this: I now get a UI exception every time I try
>>> >> to provision a disk, although it does succeed so. I'm guessing
>>> >> something else is going on, but there is no error in the engine log.
>>> >>
>>> >> On Fri, Dec 9, 2016 at 2:54 PM, cmc <iucounu@gmail.com> wrote:
>>> >> > Hi,
>>> >> >
>>> >> > I'm trying to delete a disk from a host I have shut down, as I need
>>> >> > to
>>> >> > provision a larger one. When I try to delete it, it gives me an
>>> >> > exception on the UI. I've tried removing the bootable flag, and
>>> >> > creating another disk, but it still won't allow the deletion of the
>>> >> > disk. I can't see a relevant error in the engine log, though there
>>> >> > are
>>> >> > errors in the UI log, but I expect that is just as result of the
>>> >> > underlying issue with deleting the disk.
>>> >> >
>>> >> > Thanks,
>>> >> >
>>> >> > Cam
>>> >> _______________________________________________
>>> >> Users mailing list
>>> >> Users@ovirt.org
>>> >> http://lists.phx.ovirt.org/mailman/listinfo/users
>>> >
>>> >
>>
>>