2008/11/13 Emmanuel Lacour <[EMAIL PROTECTED]>: > Dear kvm users/developpers, > > I have a problem here where the network interface of a guest hang > 2 or 3 times a day. No more packets can be sent out or received, no > error in guest or host logs. I have to stop networking, remove module, > then modprobe again and start the network to get back connection. > > My setup: > host: debian etch, kernel 2.6.26 amd64 (etch backports), kvm 73, using > libvirt > guest: debian sarge, kernel 2.6.26 686 (from etch backports) > > > I looked at changelogs for userspace kvm tools as well as kernel but didn't > found something relevant to this problem. > > > Any help would be welcome :) > 2008/11/13 Mark McLoughlin <[EMAIL PROTECTED]>:
> > To try and narrow down what's happening, when the interface has hung, > try: > > - tcpdump on both eth0 in the guest and the tap device on the host > (tap5 in your example) > > - look for anything unusual in the stats for both those interfaces, > e.g. /proc/net/dev, netstat -s etc. > > - strace the /usr/bin/kvm process > > What you're looking for e.g. is whether a guest->host ping is failing > because the request packet isn't getting to the host or because the > reply packet isn't getting to the guest, and where exactly the packet is > being blocked. We are seeing something similar under kvm-77,76,78, with recent kernels (2.6.27.X) as well as some 26.X Basically after some time with high network load the interface stops working. what we are seeing sniffing at tap level is some arp packets going out, but no answer comes from network. Basically, it seems that the machine gets disconnected. Anyway I doubt that the host/external networks have something to do with this, as a reboot always makes the network happy again. I can't tell how much traffic flows trough the inteface prior the problem, but it seems indeed related to the amount of bytes. If someone can give me some directions on how to dig this I'll be grateful. Of course, I'm using virtio drivers. We are unable to reproduce this with full emulation devices. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
