7.2.6 Configuring the Kernel for Cluster Operation

For the correct operation of the cluster, you must configure the kernel settings shown in the following table:

Kernel Setting

Description

panic

Specifies the number of seconds after a panic before a system will automatically reset itself.

If the value is 0, the system hangs, which allows you to collect detailed information about the panic for troubleshooting. This is the default value.

To enable automatic reset, set a non-zero value. If you require a memory image (vmcore), allow enough time for Kdump to create this image. The suggested value is 30 seconds, although large systems will require a longer time.

panic_on_oops

Specifies that a system must panic if a kernel oops occurs. If a kernel thread required for cluster operation crashes, the system must reset itself. Otherwise, another node might not be able to tell whether a node is slow to respond or unable to respond, causing cluster operations to hang.

On each node, enter the following commands to set the recommended values for panic and panic_on_oops:

# sysctl kernel.panic = 30
# sysctl kernel.panic_on_oops = 1

To make the change persist across reboots, add the following entries to the /etc/sysctl.conf file:

# Define panic and panic_on_oops for cluster operation
kernel.panic = 30
kernel.panic_on_oops = 1