On 17/02/2011, at 8:40 AM, Smithies, Russell wrote: > Yep, that’s the problem – it keeps coming up with 3 ports instead of 4 and eth0 is always has a different Aggregator ID. > No idea why it does that – the other server is setup the same and it’s bonding works perfectly. I would think then it might be switch related. What brand/model of switch do you have? Looking at the Wikipedia page for Link aggregation[1], it seems that 802.3ad mode creates groups from ports that share the same speed and duplex settings. There is also an implication that support has to be present on the switch, so I certainly wouldn't rule that out. [1] http://en.wikipedia.org/wiki/Link_aggregation With regard to your Xen instances, ensure that there is only interacting with bondX interfaces, and not ethX. Check inside /etc/xen/vif-bridge and network-bridge... bridging could certainly be a factor so you ought to take down your Xen instances and see if it works. Also, can you see any LACP frames going in and out of all of the interfaces? -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20110218/fc4a9786/attachment-0004.html>