By default, a fenced node in an OCFS2 cluster restarts instead of panicking so that it can quickly rejoin the cluster. If the reason for the restart is not apparent, you can change the node's behavior so that it panics and generates a vmcore for analysis.

To configure a node to panic when it next fences, run the following command on the node after the cluster starts:

# echo panic > /sys/kernel/config/cluster/cluster_name/fence_method

where cluster_name is the name of the cluster. To set the value after each reboot of the system, add this line to /etc/rc.local. To restore the default behavior, set the value of fence_method to reset instead of panic and remove the line from /etc/rc.local.

For more information, see Section 22.3.5, “Configuring the Behavior of Fenced Nodes”.