Re: Network with QEMU generated image (guix system vm)?

[Aljosha Papsch <lists@rpapsch.de>]

On 26.09.2016 19:30, Jan Nieuwenhuizen wrote:
> What I don't understand: sometimes the clone works instantly, sometimes
> I need to "wait a bit" until cloning or `ping gitlab.com' works.  It
> seemed to be always immediately available when I added the mcron and
> rottlog test services, which confuses me even more.  Might just be
> coincidence.
>
> Greetings,
> Jan
>
I'm guessing here but it sounds alot like neighbor discovery being slow 
with ARP. I had the same issue few months ago with GNS3 where I created 
a virtual topology. They use qemu VMs for each host. After creating 
topology I wanted to ping a little and some packages would be dropped 
before they went through.

http://wiki.qemu.org/Documentation/Networking suggests in section 
"Network backend types" that user networking is slow while tap 
networking is fast. So ARP discovery performance might just suffer from 
qemu user networking. Maybe it's worth trying tap networking. I used it 
a few weeks ago (with lxc containers) and it's pretty flexible. Haven't 
paid attention to performance though.

I might be able to dig up notes on topology if you are interested. In 
it, hypervisors form a VPN and integrate guests in the VPN using taps 
and bridges. It's not a guix recipe unfortunately, just a Gnome Dia file.

Best regards