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5.4.11. Kdump


This screen is disabled by default. To enable it during the installation, you must use the inst.kdump_addon=on option at the boot menu. See Section 8.2.5, “Advanced Installation Options” for details, and Section 4.2, “The Boot Menu” for instructions on using custom boot options.
Use this screen to select whether or not Kdump will be activated on the installed system, and how much memory will be reserved for it if enabled.
The Kdump configuration screen, showing 128 MB reserved
Figure 5.22. Kdump

Kdump is a kernel crash dumping mechanism which, in the event of a system crash, captures the contents of the system memory at the moment of failure. This captured memory can then be analyzed to find the cause of the crash. If Kdump is enabled, it must have a small portion of the system's memory (RAM) reserved to itself. This reserved memory will not be accessible to the main kernel.
To enable Kdump on the installed system, check Enabled. Then, select either Automatic or Manual memory reservation settings, and if you selected Manual, enter the amount of memory to be reserved in megabytes into the Memory to be reserved field.
The amount of memory which you should reserve is determined based on your system's architecture (AMD64 and Intel 64 will have different requirements than IBM Power, for example) as well as the total amount of system memory. In most cases, automatic reservation will be satisfactory. If you insist on manual settings, see the Red Hat Enterprise Linux 7 Kernel Crash Dump Guide for guidelines. This document also contains more in-depth information about how Kdump works, how to configure additional settings, and how to analyze a saved crash dump.
The Usable System Memory readout below the reservation input field shows how much memory will be accessible to your main system once your selected amount of RAM is reserved.


Additional settings, such as the location where kernel crash dumps will be saved, can only be configured after the installation using either the system-config-kdump graphical interface, or manually in the /etc/kdump.conf configuration file.
After configuring Kdump settings, click Done in the top left corner to return to Section 5.4.2, “Installation Summary”.