Enabling Kernel Crash debugging on RHEL5

To install and set up KDump, the Kernel crash dump tool for Red Hat Enterprise Linux 5:

  shell# yum install kexec-tools
  shell# chkconfig --level 2345 kdump on
  shell# chkconfig --list kdump
    kdump 0:off 1:off 2:on 3:on 4:on 5:on 6:off

Set up your config options by running this (requires X-Forwarding if you're working over SSH)
  shell#  system-config-kdump

This will add to your Grub boot line the following (192 is what I had chosen for MBs in the previous tool)
    crashkernel=192M@16M

and this requires a reboot for KDump to take effect:
"
Changing Kdump settings requires rebooting the system to reallocate memory accordingly. You will have to reboot the system for the new settings to take effect.
"

More info for config and debugging available at Red Hat.  After a reboot, info about forcing a crash available here for testing purposes.