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kdump-config

kdump-config

Section: Linux System Administrator's Manual (8) Updated: April 2007
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NAME

kdump-config - configure kdump, check status, or save a vmcore file  

SYNOPSIS

kdump-config { help | test | show | status | load | unload | savecore }
 

DESCRIPTION

kdump-config

manages the kdump feature of the Linux kernel. When a kdump enabled kernel panics, it immediately boots into a clean kernel called the kdump kernel. The memory image of the panicked kernel will be presented in /proc/vmcore while the kdump kernel (or "capture kernel") is running.

kdump-config loads the kdump kernel into the current kernel and after a kdump, captures the vmcore image via kdump kernel. kdump-config can take advantage of the linux-image-$(uname -r)-dbg package and will try to use makedumpfile to capture the vmcore. The crash tool can then be used to analyze the vmcore at a later time.

kdump-config exits with 0 on success and 1 on failure.  

COMMANDS

help
Print a usage summary.
test
Determine the parameters that would be used to load the kdump kernel, but do not load the kdump kernel. Useful for evaluating your configuration settings.
show
Show current parameters and the saved kexec command from the last kdump-config load.
status
Evaluate /sys/kernel/kexec_crash_loaded
 and print a corresponding message.
load
Load the kdump kernel.
unload
Unload the kdump kernel.
savecore
If /proc/vmcore exists, save it using makedumpfile.

 

FILES

/etc/init.d/kdump-tools
init script to automatically load a kdump kernel, or save a vmcore and reboot.
/etc/default/kdump-tools
configuration file
/var/crash/kernel_link
a link to the current debug kernel
/var/crash/kexec_cmd
the last kexec_cmd executed by kdump-config
 

DIAGNOSTICS

USE_KDUMP is not set or zero
The variable USE_KDUMP in the file /etc/default/kdump-tools
 is 0.  To use kdump, edit the file and change the value to 1.
kdump is not supported by this kernel
The file /sys/kernel/kexec_crash_loaded does not exist. This means that the currently running kernel either was not configured to support kdump, or that a crashkernel= commandline parameter was not used when the currently running kernel booted.
no crashkernel= parameter in the kernel cmdline
a crashkernel= commandline parameter was not used when the currently running kernel booted. You will need to add a crashkernel= parameter to your /etc/lilo.conf, /etc/elilo.conf or grub /boot/grub/menu.lst file and reboot, before kdump will work. See installed READMEs for suggestions.

could not find an installed debug vmlinux image and
DEBUG_KERNEL is not specified in /etc/default/kdump-tools
Warning: makedumpfile will be limited to -d 1.
A debug version of the currently booted kernel could not be found.
KDUMP_KERNEL does not exist: $KDUMP_KERNEL
A KDUMP_KERNEL was specified in /etc/default/kdump-tools, but it cannot be found.
KDUMP_INITRD does not exist: $KDUMP_INITRD
A KDUMP_INITRD was specified in /etc/default/kdump-tools, but it cannot be found.

no KDUMP_KERNEL in $KDUMP_DEFAULTS and
can't find a kdump package directory in /usr/lib
no kdump kernel could be found.

found a linux-kdump package in $KDUMP_PKG_DIR
but can't find a kdump kernel in $KDUMP_PKG_DIR
this indicates a broken linux-kdump package installation.

no kdump initrd image: $KDUMP_INITRD
an initrd will not be used
this indicates that although a kdump kernel was found, a corresponding initrd was not found.
kdump kernel relocation address does not match crashkernel= parameter
For non-relocatable architectures, the kdump kernel must be built with a predetermined start address. This message indicates that the start address of the kdump kernel and the start address in the crashkernel= parameter do not match.
failed to load kdump kernel
kexec reported that it could not load the kdump kernel.
failed to unload kdump kernel
kexec reported that it could not unload the kdump kernel. Run 'kexec -u' directly for more detail.
makedumpfile failed, falling back to 'cp'
this message is printed if the kdump-tools init script attempts to save a /proc/vmcore file using makedumpfile and the save fails.
failed to save vmcore in $KDUMP_STAMPDIR
this message indicates that makedumpfile and the fallback method of using cp has failed. This usually occurs if pathnames are wrong or if the disk is full.
 

SEE ALSO

/usr/share/doc/kdump-tools/README
/usr/share/doc/kdump-tools/README.Debian
kdump-tools(5), kexec(8), crash(8), gdb(1), makedumpfile(8)  

AUTHOR

Terry Loftin <terry.loftin@hp.com>


 

Index

NAME
SYNOPSIS
DESCRIPTION
COMMANDS
FILES
DIAGNOSTICS
SEE ALSO
AUTHOR

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Time: 22:01:52 GMT, April 16, 2011