[CentOS-virt] VMs failing to restart

[Lars Hecking]

> Have you tried other virtual network cards, and/or PV network (netback
> for Xen or virtio for KVM)?
 
 Under CentOS5/Xen, I was always using the default NIC, and I disctinctly
 remember I wasn't the only one in my team experiencing this problem.
 For CentOS6/kvm, I switched from the default to the e1000 at some point,
 but can't remember when. It was definitely working before and after I
 switched; so yes, this might have to do with the e1000.

> That would help you isolate whether the problem was in the e1000
> emulation (which I suspect is shared between KVM and Xen) or in the
> host network configuration (which, it sounds like, is non-trivial).

 As this is a production system, I'd have to set up a clone and experiment
 with different options. I have an identical host machine, so no problem
 in that regard, but this will take some time I don't currently have.