Hi Yih, On 09/08/2012 06:06 PM, Yih Chuang wrote:

During concurrent 80 VM creation, each VM takes two network connections, libvirtd failed to respond. Neither restart libvirtd nor restart CIMOM helped.

I had a little surprise last week that might just be the thing ruining your party too. I found out that [it seems] libvirtd has a global lock of some sort that blocks all operations until a VM starts. That includes the runtime of startup hook script as well. I have a "prepare" QEMU script hook that takes a while - I use it to set up volumes on first run and until that hook finishes running the entire libvirtd daemon remains totally unresponsive. All queries, no matter if issued through the API (I use the python bindings) or virsh get blocked and are unblocked only after the hook finishes. Now, I guess I'm abusing that hook and I should be setting up my volumes elsewhere, but still this came to me as a surprise. Anyway, you might want to check if some of your VM's run fancy hooks or have some other reason that makes their preparation or start up too slow. Best, Hristo