I am running Xen 3.2.1 under a Gentoo 2.6.21-xen kernel.
I have four domains running under a single dom0, two hvm: Windows XP and
Windows 2k3, and two pv: a Gentoo 2.6.25 kernel, and a Ubuntu 2.6.24
kernel. I have also experienced the same behaviour under a 2.6.21-xen
All the domU networks are bridged to a single 1gb nic, and I have tried
an alternative physical nic. There is very little load on this nic -
this is a test environment.
At a certain point that I have not established exactly, the network load
takes out the pv network. For example, if I initiate a bittorrent
session in a pv domU, I get a slow build up of network load, and then
connectivity is lost to both of the pv domU's. If I console into them,
they cannot ping outside the network, but they can ping their own
interfaces. A tcpdump on the dom0 physical shows no traffic. However,
during all this, the hvm domains are able to use their network
connections without issues.
A shutdown of the broken domU doesn't work, as they have nfs shares
loaded and it hangs on the nfs unmount, but I suspect that without this
they would shutdown cleanly. In any case, I have to destroy them. If
I attempt to recreate, I get:
Error: Device 0 (vif) could not be connected. Hotplug scripts not
The xend log only shows:
[2008-08-31 19:14:11 5531] DEBUG (DevController:595)
[2008-08-31 19:15:51 5531] DEBUG (XendDomainInfo:1897)
Although the hvm domUs are still working, if I shut them down, they hang
on start up, again with the vif problem.
I used the bittorrent example above to demonstrate it is at a certain
traffic load, however if I do a large cp from the domU to an nfs share,
it will fail almost instantly.
Restarting xend has no effect. The only thing I can fix the problem
with is a reboot of the dom0.
Here is the dom0 kernel line:
module /xen-2.6.21-noreal root=/dev/sda2 max_loop=255
(the noreal just refers to the realtek drivers being removed from the
kernel, as I tried to use realteks own drivers on their website to
resolve the problem, but the behaviour is the same).
Here is the domU cfg:
kernel = '/xen/kernels/xen-2.6.25-pae'
ramdisk = '/etc/xen/kernels/initramfs-genkernel-x86-2.6.25-gentoo-r7-ich10'
extra = 'console=hvc0'
memory = '768'
disk = [
name = 'zenayon'
vif = ['bridge=eth1, mac=00:16:3E:11:11:12']
cpu_cap = 100
The dmesg of the dom0 and domU don't have any clues that I can see, nor
log/messages, nor the xen logs.
I am at a bit of a loss as to how to diagnose this. All the other
networking related issues seem to have been resolved in earlier releases
and/or are related to routed mode. It seems to be related to the dom0
kernel or xend, as these are the things that haven't changed in my
testing. Perhaps I have a setting in my dom0 kernel that is not compatible?
Thanks for any help,
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