Re: [Qemu-devel] Stalls on Live Migration of VMs with a lot of memory

[Shu Ming]

On 2012-1-4 2:04, Peter Lieven wrote:
> Hi all,
>
> is there any known issue when migrating VMs with a lot of (e.g. 32GB) 
> of memory.
> It seems that there is some portion in the migration code which takes 
> too much time when the number
> of memory pages is large.
>
> Symptoms are: Irresponsive VNC connection, VM stalls and also 
> irresponsive QEMU Monitor (via TCP).
>
> The problem seems to be worse on 10G connections between 2 Nodes (i 
> already tried limiting the
> bandwidth with the migrate_set_speed command) than on 1G connections.
Is the migration  accomplished finally? How long will that be?  I did a 
test on VM with 4G and it took me about two seconds.


> The problem also seems to be worse in qemu-kvm-1.0 than in 
> qemu-kvm-0.12.5.
>
> Any hints?
>
> Thanks,
> Peter


--
Shu Ming<address@hidden>
IBM China Systems and Technology Laboratory