[ovs-discuss] Bonding problems with redundant physical switching

Christian Fischer christian.fischer at easterngraphics.com
Fri Sep 10 20:48:12 UTC 2010


On Friday September 10 2010 21:36:50 Ben Pfaff wrote:
> On Fri, Sep 10, 2010 at 09:23:30PM +0200, Christian Fischer wrote:
> > I try to get nic bonds working with OpenvSwitch-0.99.2 (XCP-0.5.0).
> > Due to missing xcp administration documentation I've started with the
> > XenServer-5.6 administration guide.
> >
> > There is stated that SLB bonding is an active/active mode.
> >
> > If I create bonds with OpenvSwitch then they are active/passive.
>

Thanks Ben for the reply.

> The SLB bonding implemented by Open vSwitch is indeed active/active.
> Please explain why you think that it is active/passive.

The bond is not reponding to packages arriving eth1, that's why I thought eth1 
is passive.

# ovs-appctl bond/show bond0
updelay: 200 ms
downdelay: 0 ms
next rebalance: 562 ms
slave eth1: enabled
slave eth0: enabled
        active slave
        hash 44: 1 kB load
                00:15:17:de:dd:c8

Is it active/active for sending or for sending and receiving?

>
> Also, Open vSwitch 0.99.2 is from February.  The latest release is
> 1.1.0-pre1, and 1.1.0-pre2 will be out soon.

Yes, I know, but xcp-0.5 comes with 0.99.2.

>
> > I've redundant physical switching for the bond networks, but without
> > spanning tree support (HP 1810G), therefore no inter switch links. If
> > on one side NIC0 active and on the other side NIC1 active then
> > connectivity is broken.  Normally i would think that it should be
> > possible to create a trunk between two nodes running identical trunk
> > mode without any switching, in this case there's also no ISL.
>
> I don't understand this paragraph.

All physical cluster nodes have different physical networks, 2 network 
interfaces bonded each. There are two physical switches, the networks have 
different VlanIDs. There's no network link between both switches, the 
switches have no spanning tree protocol support.

My testnetwork is untagged, no vlan on top of the bond.

If NIC one of host one is active and NIC two of host two is active the 
inactive slaves receive the packages send by the active slaves, and the hosts 
don' respond.

Shouldn't both slaves listen for incoming packages?
What should happen if one connects two hosts with two bonded NICs each 
directly without any switches?

>
> > What is best practice for nic bonding with redundant switching and is
> > that described bond behavior normal for OpenvSwitch SLB mode?
>
> With Open vSwitch bonding, you plug both (or all) of the bonded ports
> into the same switch.  It's not a way to obtain redundant switching.
>
> If you want to use another form of bonding, you can use OVS with Linux
> bonding.  Linux supports multiple forms of bonding.







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