Detecting network interface failures

If you are running a single-node or two-node cluster, more configuration is required to detect network interface failures.

The cluster software periodically tries to contact each network interface in the cluster. If the attempt to contact an interface fails on one node of a two node cluster, the corresponding interface on the other node is also flagged as offline. It is flagged as offline, because it does not receive a response from its peer.

To avoid this behavior, the cluster software must be configured to contact a network instance outside of the cluster. You may use the default gateway of the sub-net the interface is in.

On each node, create the following file:

/var/ct/cfg/netmon.cf

Each line of this file contains the system name or IP address of the external network instance. IP addresses can be specified in dotted decimal format.

Example of a netmon.cf file:

#This is default gateway for all interfaces in the subnet 192.168.1.0 
192.168.1.1

# This is default gateway for all interfaces in the subnet 192.168.2.0 
gw.de.ibm.com