[ovirt-users] Logical Networks with different MTUs

[Cam Wright]

Hi,

I've just started building an oVirt farm as a replacement for our
existing infrastructure and I'm having issues configuring multiple
VLAN bridges with different MTUs.

When I try to add a logical network with a VLAN tag + VM Network + MTU
9000 to a bonded interface on my host with only the ovirtmgmt network
(MTU 1500, default) it throws up an error message and won't let me
continue, error message below:

Cannot setup Networks. The following Logical Networks do not have the
same MTU value: ovirtmgmt(default),
net_bne_vlan10(9000).

Eventually, I will want to add more logical networks with the default
MTU, so setting the ovirtmgmt MTU to 9000 is unfortunately not going
to solve my issue.

This is something I can do in vanilla Linux networking where I set the
802.3ad bond to be MTU 9000 and configure two different bridges off
that interface to 1500 and 9000, however this does not seem to be
possible in the oVirt web interface.

I've dug through the Administration guide and feature requests and
there doesn't seem to be anything there around using different MTU
values for different logical networks.

Has anyone been able to successfully do this? The
/etc/sysconfig/network-scripts and /var/lib/vdsm/persistence/netconf
files seem to get rewritten whenever the vdsm service does anything,
so I'm reluctant to edit them manually.

The hosts were built using the hosted-engine installer on Fedora 22.
The engine is running Fedora 22 also, see below:

[root at bne-ovirtengine01 ~]# cat /etc/redhat-release
Fedora release 22 (Twenty Two)
[root at bne-ovirtengine01 ~]# uname -r
4.0.4-301.fc22.x86_64

oVirt Engine Version: 3.6.0-1.fc22

Any assistance would be appreciated.

Cam Wright | Systems Administrator
CUTTINGEDGE
90 Victoria St, West End, Brisbane, QLD, 4101
T +61 7 3013 6222
E cwright at cuttingedge.com.au | W www.cuttingedge.com.au

/SYD /BNE /MEL /TYO