See this?

bond0: Warning: failed to get speed and duplix from eth*

Do this:

insmod bonding miimon=100

why?⌗

When using Linux network bonding the kernel may be to quick to enslave the interfaces. When an interface is too slow to report it capabilities it will be set to 100Mbit and Full Duplex. Which is a bit sad when you have 6 Gigabit network cards…