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kdumpctl - Man Page

control interface for kdump


kdumpctl COMMAND


kdumpctl is used to check or control the kdump service. In most cases, you should use systemctl to start / stop / enable kdump service instead. However, kdumpctl provides more details for debugging and a helper to set up ssh key authentication.



Start the service.


Stop the service.


Prints the current status of kdump service. It returns a non-zero value if kdump is not operational.


Is equal to start; stop


reload the crash kernel image and initramfs without triggering a rebuild.


rebuild the crash kernel initramfs.


Helps to setup key authentication for ssh storage since it's impossible to use password authentication during kdump.


Prints the size of reserved memory for the crash kernel in megabytes.


Estimate a suitable crashkernel value for the current machine. This is a best-effort estimate. It will print a recommended crashkernel value based on the current kdump setup, and list some details of memory usage.


Return the default crashkernel value provided by kexec-tools.

reset-crashkernel [--kernel=path_to_kernel] [--reboot]

Reset crashkernel to default value recommended by kexec-tools. If no kernel is specified, will reset KDUMP_KERNELVER if it's defined in /etc/sysconfig/kdump or the current running kernel's crashkernel value if KDUMP_KERNELVER is empty. You can also specify --kernel=ALL and --kernel=DEFAULT which have the same meaning as grubby's kernel-path=ALL and kernel-path=DEFAULT. ppc64le supports FADump and supports an additional [--fadump=[on|off|nocma]] parameter to toggle FADump on/off.

Note: The memory requirements for kdump varies heavily depending on the used hardware and system configuration. Thus the recommended crashkernel might not work for your specific setup. Please test if kdump works after resetting the crashkernel value.

See Also

kdump.conf(5), mkdumprd(8)

Referenced By

kdump.conf(5), kdumpctl_selinux(8).

2015-07-13 kexec-tools