Re: [Qemu-discuss] vm get stuck during snapshot commit with qemu-img

[Jakob Bohm]

On 18/07/2017 09:05, Hans-Juergen Rux wrote:
> Morning,
>
>
> We have the following problem and we have absolut no idea how to fix it.
>
>
>
> We are using CentOS 7.2 / 7.3 with KVM (qemu 2.6). Everything works really 
> great with VM image files (qcow2) under about ~700/800 GB. It is fast and works 
> fine, interruptions of the VM during snapshot commit into base file of max 1 
> second.
>
>
>
> But when we build virtual servers with disk images >1-2 TB or more, and commit 
> snapshots from a snapshot chain into the basefile, we have interruptions in the 
> virtual machines of 30-60 seconds. Ping to the VMs is interrupted, the RDP 
> sessions are lost. The time inside VM jumps.
>
>
>
> It seems that the timeout happens at the end of the commit proccess.
>
>
>
> The same on different HW, diferrent disk subsystems, different Windows or Linux 
> VMs. So regardless of whether the drive on VM operating system has a paritition 
> on ist virtual disks or the qemu guest-agent is installed.
>
>
>
> Any ideas?
I have experienced similar misbehavior on Debian, also with an
"old" qemu version.

I don't know if these issues have been fixed in a later upstream
qemu version, and if so, which one.


Enjoy

Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
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