46.2.3. Configuring kdump on the Command Line Configuring the Memory Usage

To configure the amount of memory that is reserved for the kdump kernel on x86, AMD64, and Intel 64 architectures, open the /boot/grub/grub.conf file as root and add the crashkernel=<size>M@16M parameter to the list of kernel options as shown in Example 46.1, “Sample /boot/grub/grub.conf file”.


Unless the system has enough memory, the kdump crash recovery service will not be operational. For information on minimum memory requirements, refer to the Red Hat Enterprise Linux comparison chart. When kdump is enabled, the minimum memory requirements increase by the amount of memory reserved for it. This value is determined by the user and on x86, AMD64, and Intel 64 architectures, it defaults to 128 MB plus 64 MB for each TB of physical memory (that is, a total of 192 MB for a system with 1 TB of physical memory).

Example 46.1. Sample /boot/grub/grub.conf file

# grub.conf generated by anaconda
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/sda3
#          initrd /initrd-version.img
title Red Hat Enterprise Linux Server (2.6.18-274.3.1.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-274.3.1.el5 ro root=/dev/sda3 crashkernel=128M@16M
        initrd /initrd-2.6.18-274.3.1.el5.img