[libvirt-users] Networking issues in host

[G. Richard Bellamy]

I realize this falls under the category of "so incredibly vague I
should maybe not send it", so I have low expectations and apologize
beforehand if it's just pure noise.

That being said - it appears that the whole HOST system becomes laggy.
It can effect the mouse, the keyboard, the network. There are no
messages in the logs that I can find that indicate the system is
blocked or hung or dumping core - and frankly I just don't know where
to start troubleshooting something like this when there's absolutely
no indication in the logs that things are struggling.

What I DO know about the symptoms:
1. happen after an indeterminate period of time
2. continue even if I shutdown libvirtd and the two guests - a reboot
is REQUIRED
3. do NOT occur if I leave libvirtd disabled and NEVER start it

Which, on review, seems it might have something to do with the KVM
kernel module - so I'm copying that mailing list as well.

root at eanna i ~ # pacman -Qi linux
Name           : linux
Version        : 3.18.6-1
Description    : The Linux kernel and modules
Architecture   : x86_64
...
Build Date     : Fri 06 Feb 2015 11:46:13 PM PST
Install Date   : Thu 19 Mar 2015 03:58:50 PM PDT
Install Reason : Explicitly installed
Install Script : Yes
Validated By   : None
root at eanna i ~ # modinfo kvm
filename:       /lib/modules/3.18.6-1-ARCH/kernel/arch/x86/kvm/kvm.ko.gz
license:        GPL
author:         Qumranet
depends:
intree:         Y
vermagic:       3.18.6-1-ARCH SMP preempt mod_unload modversions
parm:           ignore_msrs:bool
parm:           min_timer_period_us:uint
parm:           tsc_tolerance_ppm:uint
parm:           allow_unsafe_assigned_interrupts:Enable device
assignment on platforms without interrupt remapping support. (bool)
root at eanna i ~ # grep -P "^(?\!#).*GRUB_CMDLINE" /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_osi=Linux iommu=pt iommu=1
transparent_hugepage=never"
GRUB_CMDLINE_LINUX=""


On Wed, Mar 25, 2015 at 9:53 AM, G. Richard Bellamy
<rbellamy at pteradigm.com> wrote:
> I've been having intermittent network issues on my Host - they go away when
> I stop and disable libvirtd and then reboot. They do not go away if I just
> stop libvirtd and don't reboot.
>
> I'm at a loss as to where to start with my troubleshooting, and being a
> relative n00b to libvirt, I'd love any pointers.