Intel 4-port ethernet adaptor link aggregation issue

[Joe Moog]

On Aug 1, 2013, at 4:27 PM, Joe Moog <joemoog at ebureau.com> wrote:

> On Aug 1, 2013, at 3:55 PM, Ryan Stone <rysto32 at gmail.com> wrote:
> 
>> Have you tried using only two ports, but both from the NIC?  My suspicion would be that the problem is in the lagg's handling of more than 2 ports rather than the driver, especially given that it is the igb driver in all cases.
> 
> Ryan:
> 
> We have done this successfully with two ports on the NIC, on another hardware-identical host. That said, it is entirely possible that this is a shortcoming of lagg. 
> 
> Can you think of any sort of workaround? Our desired implementation really requires the inclusion of all 4 ports in the lagg. Failing this we're looking at the likelihood of 10G ethernet, but with that comes significant overhead, both cost and administration (before anybody tries to force the cost debate, remember that there are 10G router modules and 10G-capable distribution switches involved, never mind the cabling and SFPs -- it's not just a $600 10G card for the host). I'd like to defer that requirement as long as possible. 4 aggregated gig ports would serve us perfectly well for the near-term.
> 
> Thanks
> 
> Joe

UPDATE: After additional testing, I'm beginning to suspect the igb driver. With our setup, ifconfig identifies all the ethernet ports as igb(0-5). I configured igb0 with a single static IP address (say, 192.168.1.10), and was able to connect to the host administratively. While connected, I enabled another port as a second standalone port, again with a unique address (say, 192.168.1.20), and was able to access the host via that interface as well. The problem arises when we attempt to similarly add a third interface to the mix -- and it doesn't seem to matter what interface(s) we use, or in what order we activate them. Always on the third interface, that third interface fails to respond despite showing "active" both in ifconfig and on the switch.

If there is anything else I could try that would be useful to help identify where the issue may reside, please let me know.

Thanks

Joe