[Linux-cluster] Cman (and corosync) starting before network interface is ready

[Rick Stevens]

On 09/17/2014 08:20 AM, Vallevand, Mark K issued this missive:
> Tried replacing the switch with a crossover cable.  The problem goes
> away.  It looks like there is some odd delay in the switch.  The NIC is
> configured, but it takes 4 seconds for the link to go up.  Huh.
>
> We have a dedicated network for all the cluster traffic.  Nothing else
> uses it.  In the two-node case, we use a cable.  In larger clusters we
> will use a switch.  First delivery is for two-node clusters.  But, I
> worry about that slow switch.

Switches have to negotiate speeds, protocols, check for conflicting MACs 
and several other things (depending on the switch/router). It is
possible for that to take a couple of seconds.

I'll bet that if you unplug the cable from the switch, then plug it
back in, you'll probably notice a slight delay in the port's link LED
lighting up as well. Pretty common and not necessarily indicative of a
problem.
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- Rick Stevens, Systems Engineer, AllDigital    ricks at alldigital.com -
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