[libvirt] save/ restore a domain with kvm

[Zvi Dubitzky]

Thanks

a Question if I may.
Are you familiar with the cpuTime of a  VM that we get by libvirt from 
virDomainInfoPtr  struct .
Is that the real cpuTime of all the vcpus of a VM  together  ?
e.g   if I  sample this cpuTime   at 2 times apart by 'n' secs  and get 
cpuTime1 and cpuTime2 , then if  the  VM has 4 vcpus and they are fully 
utilized,
 I will get :  (vcpuTime- vcpuTime1) =  4 *n  . That is  each of the 4 
vcpus are fully utilizing the 'n' secs .


thanks

Zvi Dubitzky 
Virtualization and System Architecture   Email:dubi at il.ibm.com
IBM Haifa Research Laboratory    Phone: +972-4-8296182
Haifa, 31905, ISRAEL 





Dor Laor <dlaor at redhat.com> 
23/03/2009 15:24
Please respond to
dlaor at redhat.com


To
Zvi Dubitzky/Haifa/IBM at IBMIL
cc
"Daniel P. Berrange" <berrange at redhat.com>, libvir-list at redhat.com
Subject
Re: [libvirt] save/ restore a domain with kvm






Zvi Dubitzky wrote:
> Forgot to say: I am working with kvm-72
> Does that have implication on the correctness of the save/restore of VM 
> state ?
>
>
> 
Save-restore on upstream kvm versions is rather error prone.
I'm note sure one version is better than the other. Evan today mainline 
kvm's
migration is not stable. We'll send patches this week to fix that.

So bottom line, if it works for you, use it.
> Zvi Dubitzky 
> Virtualization and System Architecture   Email:dubi at il.ibm.com
> IBM Haifa Research Laboratory    Phone: +972-4-8296182
> Haifa, 31905, ISRAEL 
>
>
>
>
>
> "Daniel P. Berrange" <berrange at redhat.com> 
> 23/03/2009 11:36
> Please respond to
> "Daniel P. Berrange" <berrange at redhat.com>
>
>
> To
> Zvi Dubitzky/Haifa/IBM at IBMIL
> cc
> libvir-list at redhat.com
> Subject
> Re: [libvirt] save/ restore a domain with kvm
>
>
>
>
>
>
> On Sun, Mar 22, 2009 at 08:04:17PM +0200, Zvi Dubitzky wrote:
> 
>> I am working with virsh 
>>
>> The version of  VIRSH as it shows is :
>> virsh # version
>> Compiled against library: libvir 0.4.4
>> Using library: libvir 0.4.4
>> Using API: QEMU 0.4.4
>> Running hypervisor: QEMU 0.9.1
>>
>> Under virsh  I do the following :
>> 1.  suspend a running VM 
>> 2. save it to a file  with the 'save' command 
>> 3. restore the saved domain file  with the 'restore' command while the 
>> domain is still in the suspend mode
>>     or after it was shutdown/destroyed (not seen with 'list --all)
>>     In either case I get the error message  saying :
>>
>>    virsh # restore /home/dubi/xml/vm_dubi2.sav
>>   libvir: QEMU error : operation failed: failed to start VM
>>   error: Failed to restore domain from /home/dubi/xml/vm_dubi2.xml
>>
>> Any idea what is the failure reason  ?
>> 
>
> Check the /var/log/libvirt/qemu/$HOME.log file for more information from
> QEMU
>
> Daniel
>