[Linux-cluster] Multiple links to a cluster

Michael O'Sullivan michael.osullivan at auckland.ac.nz
Fri Dec 12 01:32:56 UTC 2008

Hi everyone,

I have been trying to set up a 2-node cluster where both nodes have 
multiple links to the cluster. Initially, I specified two IP addresses 
for each cluster node in /etc/hosts, but this seemed to confuse the 
fencing and make the cluster hang.

Now I am trying to use a link equalizer (TEQL device, see the Linux 
Advanced Routing and Traffic Control - lartc.org for details) which uses 
a single IP address and shares the load across the two links. However, 
some packets may be delivered out of order...

Unfortunately, using the TEQL device makes the 2-node cluster have a 
split-brain problem that I can't seem to remedy. I changed /etc/hosts to 
use one of the actual NICs instead of the TEQL device and got the 
cluster going, but as soon as I go back to the TEQL device node 1 thinks 
node 2 is offline and node 2 thinks node 1 is offline...

Does anyone have any suggestions to fix this? Or alternatives for using 
a single IP address? (Note, I have not used ethernet bonding as it does 
not utilize the full capacity of both links whereas I think TEQL will.)

I'm happy to supply any extra information required. Thanks in advance 
for any help, Mike

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