[SOLVED] Best way to pause KVM/QEMU windows guest

abdulmoeed · 07-29-2015, 11:57 AM

When I pause my guest using following

Code:

virsh suspend <domain>

But the process qemu-system-x86_64 keeps taking about 30% of CPU (and this annoys be)

I am able to pause the guest by pausing the process with following command

Code:

kill -STOP `pidof qemu-systemx86_64`

this takes the CPU usage to 0, which is quite satisfying

and I haven't seen any side affects of this approach till now.

So my question is, are there any problems I may run into using the later approach, like corruption of the guest.

Also why doesn't the actual suspend command actually suspends everything about the guest.

pan64 · 07-30-2015, 05:15 AM

sigstop is the right signal to stop (hang) a process (that does not mean to terminate and/or kill it) and sigcont is used to allow to run it again. That will not corrupt anything, but keep in mind stopped processes are unresponsive (so cannot react on keyboard-mouse event for example).

qemu-system-x86_64 is the kvm process itself, that is not a guest, you cannot suspend it by virsh suspend. Also I think stopping that process will hang all the guests (if I remember well)

abdulmoeed · 07-30-2015, 05:44 AM

Thanks pan64, that is very good to know. Now the question remains what is the kvm process doing when to take 30% CPU even when there is no guest running.