Dell PE R515 Ethernet bonding in CentOS 6 problem

Dimitri Yioulos dyioulos at
Thu Jul 21 07:47:03 CDT 2011

On Wednesday 20 July 2011 10:41:36 am Howard Powell wrote:
> I have three Dell PowerEdge R515 systems which I have
> configured alike with CentOS 6 x86_64.  Each system has the two
> built-in Broadcom NetXtreme II adapter and an additional two
> port Broadcom NetXtreme II network card, for a total of four
> gigabit network ports per machine.  The NICs are up to date
> with the latest firmware, and I've updated the OS to it's most
> recent kernel.
> I am unable to bond the network interfaces together in CentOS 6
> like I was able to do in CentOS 5.
> In C6, I have created a bonding.conf file in /etc/modprobe.d
> and in it is the line: alias netdev-bond0 bonding
> (note that the bond0 issues a depricated warning as of the
> latest 2.6.32-71.29.1.el6.x86_64 kernel - so use the
> recommended "netdev-bond0" instead).
> I have created the file
> /etc/sysconfig/network-scripts/ifcfg-bond0 with the following:
> DEVICE="bond0"
> BOOTPROTO="static"
> DNS1="<my DNS>"
> DNS2="<my DNS>"
> DNS3="<my DNS>"
> GATEWAY="<my gateway>"
> IPADDR="<my aggregated IP address>"
> ONBOOT="yes"
> BONDING_OPTS="miimon=100 mode=6"
> I have modified the /etc/sysconfig/network-script/ifcfg-eth?
> files to each include the following: DEVICE="eth<the ethernet
> interface>"
> HWADDR="<the unique hardware address of each NIC>"
> ONBOOT="yes"
> MASTER="bond0"
> SLAVE="yes"
> If I then issue a "service network restart" command, the bond0
> interface will come up but no eth? interfaces will start.  I
> have tested this on other systems (a Dell precision T3500) and
> the eth? interfaces start correctly, as expected.  Bonding
> these NICs worked in CentOS 5.6 with no problems.
> I am able to "ifenslave bond0 eth?" each of the ethernet
> interfaces, and the connection works.  However, upon reboot,
> the system is does not start the slave interfaces and therefore
> is not available on the network until someone manually enslaves
> each interface.
> It seems that the init scripts see the SLAVE="yes" comment of
> the eth devices and ignores the interface.  As I noted though,
> bonding works on other systems but the problem I have described
> here is repeatable on each of my PE R515s.
> I'm open to ideas.  Thanks!
> Howard
> Howard Powell
> hbp4c at

I think you need the following line in bonding.conf:

options bond0 miimon=100 mode=6

or, perhaps:

options netdev-bond0 miimon=100 mode=6

In my own set-up, anyway, I don't have the line in my ifcfg-bond0:


but do have BOOTPROTO=none



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