Red Hat Enterprise Linux 5 Administration Unleashed

Saving Kernel Dumps for Analysis 439Starting and Stopping the Kdump ServiceAfter dedicating memory for the secondary kernel started with Kexec and setting the locationin which to save the dump file, start the Kdump service as root:21service kdump startNOTEEach time Kdump is started, the options from /etc/sysconfig/kdump are used suchas any additional command-line options to pass to the kernel. For most cases, this filedoes not need to be modified. The file contains comments describing each optionshould you need to modify them.Other commands include (use with service kdump ):. stop: Stop the Kdump service.. status: Determine whether or not the Kdump service is running.. restart: Stop and start the Kdump service. Must be used to enable changes to the/etc/kdump.conf file.. condrestart: If and only if the Kdump service is already running, restart it.. propagate: If an SSH server is configured in /etc/kdump.conf as the remote locationon which to save the dump file, this command must be run to enter the passphraseso the given user can transfer the dump file without being prompted for apassphrase or password.To have Kdump start at boot time, execute the following as root:chkconfig kdump onActivating Kdump with a Graphical ApplicationRed Hat Enterprise Linux also includes a graphical program for configuring Kdump. Startit by selecting Administration, Kdump from the System menu on the top panel of thedesktop or by executing the system-config-kdump command. If you are a non-root user,you are prompted for the root password to continue.As you can see from Figure 21.1, all the previously discussed options can be set, startingwith the amount of reserved memory. Click the Edit Location button to select a locationother than the default /var/crash/ directory. The Default Action pulldown menu isequivalent to the default option in kdump.conf previously described in the “AdditionalKdump Options” section. The Core Collector field is equivalent to the core_collectoroption while the Path field is equivalent to the path option that lets you set a differentdirectory to append to the selected location. Both of these options were also discussed inthe previous section “Additional Kdump Options.” The Core Collector and Path optionswill only accept input if they can be used with the selected location.