----- Original Message -----
> From: "Nico Kadel-Garcia" <[log in to unmask]>
> To: "Johan Guldmyr" <[log in to unmask]>
> Cc: [log in to unmask]
> Sent: Monday, June 2, 2014 2:40:53 PM
> Subject: Re: Replacing bridge interface online
> 
> On Mon, Jun 2, 2014 at 2:08 AM, Johan Guldmyr <[log in to unmask]> wrote:
> > Hi!
> >
> > On a SL6.5 machine we now have two connections to the same switch/vlan. One
> > is 1GbE (eth0) and the other is 10GbE (eth5).
> > Could I just do a "brctl addif br0 eth5" and then "brctl delif br0 eth0"
> > and it switch to use the 10GbE link?
> > After this we could change the network-scripts to make it work after
> > reboot.
> > Will this prevent existing connections from being cut?
> 
> You're going to hurt yourself trying to do handstands to avoid
> downtime. I suggest you accept a very short service interruption as
> one module is brought down, and the other brought up. It's easy enough
> to configure them to the same IP address and set the new one to be up
> and the old one down, then do "/sbin/service network restart"  Or you
> can bring up the second node on a second IP address for testing, then
> swap the IP addresses.

I believe what I will do is to keep the IP address on the br0,
but change ifcf-eth0 that has BRIDGE=br0 to ONBOOT=no and set 
ifcfg-eth5 to BRIDGE=br0 and ONBOOT=yes. Then a network restart ought to do it.

> 
> Unless the upstream switches support pair bonding operations, it's
> just not going to work well. See my old notes at
> https://wikis.uit.tufts.edu/confluence/display/TUSKpub/Configure+Pair+Bonding,+VLANs,+and+Bridges+for+KVM+Hypervisor
> if you really have to do this sort of thing.

Thanks, it was a bit of a long shot.
Upstream switch do support bonding but the interfaces aren't bonded.

> 
> 
> > # brctl show
> > bridge name     bridge id               STP enabled     interfaces
> > br0             8000.18a9054c4d34       no              eth0
> >                                                         vnet1
> > br4             8000.00265556f190       no              eth4
> >                                                         vnet0
> > virbr0          8000.5254009398c7       yes             virbr0-nic
> >
> >
> > // Johan Guldmyr
> > Systems Specialist
> > CSC - IT Center for Science
> > http://www.csc.fi
>