On 2012-06-28, at 3:30 PM, Kinzel, David wrote: > Jun 28, 2012 at 3:44 PM, Kinzel, David <david.kin...@encana.com> >> wrote: >>>> I'm still playing around with things. I'm seeing some weird stuff >>>> like multiple identical MAC addresses on a system. >>>> >>>> I'll figure it out... >>> >>> If you bond two devices they will both use the same. >> >> So the ifcfg-ethX file may have one MAC, but ifconfig might report another? >> >> Marco >> > > This is correct. Both eth* devices in the bond pair will share the same MAC > in ifconfig output. The Ethernet device which becomes the first setup in the > bond will be used for both (so likely eth0's MAC if you have sane naming). > >
This behaviour can be disabled in the bonding module with the "fail_over_mac" option. However, it usually makes sense to let the system duplicate the HW address of the first slave too all the other slave interfaces, in an active-backup configuration at least. This way, when the second link becomes primary, there is no traffic interruption or delay caused by ARP caches needing to be updated or cleared, or gratuitous ARP needing to be sent to force an update.. Said otherwise, the other machines in the same network will not know that a failover has occurred, since the MAC address that they use to send traffic to your machine has not changed. As others have said, it would be highly advisable to provide the HWADDR variable in your /etc/sysconfig/network-scripts/ifcfg-eth* files, to ensure that the naming of your interfaces is consistent. "/sbin/modinfo bonding" can be used to see the various options to the bonding module. You definitely want to adjust the "mode" parameter, and may also want to adjust additional parameters such as "updelay", "primary" and "primary_reselect", for example. If you wish to see the real HW addresses of your interfaces that are already enslaved into a bond master, poke around "/proc/net/bonding/bond*", look for lines that say "Permanent HW addr". HTH, Antoine Antoine Reid Conseiller Principal Principal Consultant Infrastructures Technologiques Gallium 1250, Boul. René-Lévesque Ouest Bureau 2200 Montréal (Québec) Canada H3B 4W8 M : +1 514.515.3314 F : +1 514.394.0420 E : ar...@gallium-it.com www.Gallium-IT.com _______________________________________________ rhelv5-list mailing list rhelv5-list@redhat.com https://www.redhat.com/mailman/listinfo/rhelv5-list
