Very slow and inconsistent internal network speed (between, VM's on the same host) for FreeBSD 11.0+ as guest on, XCP-ng/XenServer

[Karl Pielorz]

--On 04 July 2019 09:23 +0200 Roger Pau Monné <roger.pau at citrix.com> wrote:

> As a workaround you can switch to the emulated network card by
> setting 'hw.xen.disable_pv_nics=1' in /boot/loader.conf. That will
> give you worse performance than a fully working PV network card, but
> at least should be consistent. There are others that have switched to
> virtio-net, but I have no idea how to do that with XCP.

Just to add my $0.02's to the conversation...

As Roger knows we've had numerous issues with Xen xn based networking and 
FreeBSD guests over the years. We currently run VirtIO (vtnet) on XenServer 
7.1 and it solves all these issues (it's probably not quite as 'performant' 
as xn - but it's close for what we're using it with - it is miles better 
than e1000 performance).

Unfortunately in XenServer 7.6 virtio is no longer compiled into Qemu from 
what I can see. XCP-ng has the same issue (as it's based on XenServer) - so 
virtio is currently not an option with XCP-ng either.

e1000/rtl8139 will solve 'weirdness' (think of VM's routing traffic, doing 
DHCP or VPN duties) - but virtio solves the same issues, with much better 
performance.

I've posted to the XCP-ng forums asking if virtio can be enabled in XCP-ng 
builds (as this is probably more likely that getting XenServer to release 
with it enabled).

Aside from getting Xen xn 'fixed' for the cases it currently fails (no 
small undertaking from what I understand) - it leaves FreeBSD pretty much 
stuck, at least for some usage cases.


Regards,

-Karl