[ovirt-users] changing the mtu on bridge devices

[Gary Lloyd]

Hi Ido

I updated the database and all seemed to be OK.

Cheers

*Gary Lloyd*
________________________________________________
I.T. Systems:Keele University
Finance & IT Directorate
Keele:Staffs:IC1 Building:ST5 5NB:UK
+44 1782 733063 <%2B44%201782%20733073>
________________________________________________

On 15 November 2015 at 13:08, Ido Barkan <ibarkan at redhat.com> wrote:

> Hi Gary.
> First, In oVirt 3.6 we will enable editing a few network attributes
> while there vms attached to it.
> The reason this is forbidden is that until v3.6, by default, vdsm will
> recreate the network for
> every network edition and this can seriously disturb the network for
> the running vms.
> Second, if you want to tweak the MTU you should use 'ip link set dev
> <dev-name> mtu 9000'
> for each device in the network (Bridge, Vlan device, Bond, physical
> NIC). Then, you should edit
> vdsm persistence json files under both /var/run/vdsm/netconf/<nets/bonds>/
> and /var/lib/vdsm/persistence/netconf/<nets/bonds>/. You should find a
> file for each network/bond
> under those paths.
> On the engine DB you should find the proper row in the 'network' table
> and update the 'mtu' attribute.
> Good luck,
> Ido
>
> On Thu, Nov 12, 2015 at 4:45 PM, Gary Lloyd <g.lloyd at keele.ac.uk> wrote:
> > Hi we have upgraded to ovirt 3.5.5 and it seems to have gone well.
> However
> > when we initially configured one of our clusters (back in the day of
> ovirt
> > 3.2) we forgot to adjust two of our vm guest bridges that we use for
> iscsi
> > traffic to an mtu of 9000.
> >
> > We have around 50 or so vms using these bridges and we cant change the
> mtu
> > on the data center screen due to the vms being attached to the bridges
> (This
> > message comes up trying to change it).
> >
> > We were able to easily override the settings on the hosts in prior
> versions
> > of ovirt (but I don't remember where we did it). Our current 3.4 cluster
> is
> > fine, but I am now setting up a 3.5 cluster with new servers.
> > I don't see how changing it to 9000 will cause us any problems due to the
> > fact that our older clusters are running those bridges at 9000 anyway.
> >
> > Also has anyone experienced the new ui not being as responsive when
> showing
> > the state of vm migrations (doesn't seem to refresh very well on the
> hosts
> > screen).
> >
> > Does anyone know if there a way I can force the value to mtu 9000 in the
> > database somewhere without blowing it up ?
> >
> > Cheers
> >
> > Gary Lloyd
> > ________________________________________________
> > I.T. Systems:Keele University
> > Finance & IT Directorate
> > Keele:Staffs:IC1 Building:ST5 5NB:UK
> > +44 1782 733063
> > ________________________________________________
> >
> > _______________________________________________
> > Users mailing list
> > Users at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/users
> >
>
>
>
> --
> Thanks,
> Ido Barkan
>
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