Cannot start kdump

Question

My system always crashes down. So I decided to enable kdump to see the problem since I was not able to see possible errors on the log files.

I followed the steps to set up kdump from a site here. My server runs on CentOS 5.8 and 16GB RAM. Below are the steps I performed to configure kdump:

1. Install kexec-tools, `yum install kexec-tools` and follow the installation steps
2. Edit the /boot/grub/grub.conf to configure the kdump memory usage
3. Edit the /etc/kdump.cof to configure the target type to /var/crash/ and core_collector
4. Enable kdump through `chkconfig kdump on`.
5. Reboot the server

When I run service kdump status, it says Kdump is not operational. What should I do make the kdump operational. Did i miss something to configure? I included below the contents of my /boot/grub/grub.conf and /etc/kdump.conf

Bellow are the contents of the file /boot/grub/grub.conf

# 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
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (2.6.18-308.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-308.el5 ro root=LABEL=/
crashkernel=128M
        initrd /initrd-2.6.18-308.el5.img

Below are the contents of the file /etc/kdump.conf

# Configures where to put the kdump /proc/vmcore files
#
# This file contains a series of commands to perform (in order) when a
# kernel crash has happened and the kdump kernel has been loaded.  Directives in
# this file are only applicable to the kdump initramfs, and have no effect if
# the root filesystem is mounted and the normal init scripts are processed
#
# Currently only one dump target and path may be configured at once
# if the configured dump target fails, the default action will be preformed
# the default action may be configured with the default directive below.  If the
# configured dump target succedes
#
# For filesystem based dump, it's recommended to use UUID and LABEL
# instead of device name in dump target.
#
# See the kdump.conf(5) man page for details of configuration directives

#raw /dev/sda5
#ext3 /dev/sda3
#ext3 LABEL=/boot
#ext3 UUID=03138356-5e61-4ab3-b58e-27507ac41937
#net my.server.com:/export/tmp
#net user@my.server.com
path /var/crash
core_collector makedumpfile -c --message-level 1
#core_collector cp --sparse=always
#link_delay 60
#kdump_post /var/crash/scripts/kdump-post.sh
#extra_bins /usr/bin/lftp
#disk_timeout 30
#extra_modules gfs2
#options modulename options
#default shell
#sshkey /root/.ssh/kdump_id_rsa

I also notice that my /boot/grub/grub.conf file differs from the sample grub.conf file from the tutorial. They differ in two lines:

From tutorial
   kernel /vmlinuz-2.6.32-220.el6.x86_64 ro root=/dev/sda3
   initrd /initramfs-2.6.32-220.el6.x86_64.img

From own conf 
   kernel /vmlinuz-2.6.18-308.el5 ro root=LABEL=/
   initrd /initrd-2.6.18-308.el5.img

Could these lines cause the kdump not to start?

[EDIT 1] Content of /var/log/messages

    Feb 25 02:18:28 61540 kernel: Command line: ro root=LABEL=/ crashkernel=128M
    Feb 25 02:18:28 61540 kernel: BIOS-provided physical RAM map:
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 0000000000010000 - 000000000009a000 (usable)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 0000000000100000 - 00000000cfda0000 (usable)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 00000000cfda0000 - 00000000cfdd1000 (ACPI NVS)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 00000000cfdd1000 - 00000000cfe00000 (ACPI data)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 00000000cfe00000 - 00000000cff00000 (reserved)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)
    Feb 25 02:18:28 61540 kernel:  BIOS-e820: 0000000100000000 - 000000042f000000 (usable)
    Feb 25 02:18:28 61540 kernel: DMI 2.4 present.
    Feb 25 02:18:28 61540 kernel: No NUMA configuration found
    Feb 25 02:18:28 61540 kernel: Faking a node at 0000000000000000-000000042f000000
    Feb 25 02:18:28 61540 kernel: Bootmem setup node 0 0000000000000000-000000042f000000
    Feb 25 02:18:28 61540 kernel: Memory for crash kernel (0x0 to 0x0) notwithin permissible range
    Feb 25 02:18:28 61540 kernel: disabling kdump
    Feb 25 02:44:39 61540 kdump: No crashkernel parameter was specified or crashkernel memory reservation failed
    Feb 25 02:44:39 61540 kdump: failed to start up

[EDIT 2] Or should I change the code ro root=LABEL= into ro root=/dev/sda3?

_Or should I change the code `ro root=LABEL=/` into `ro root=/dev/sda3`?_ --> DON'T do that without understanding. — quanta, Feb 25 '13 at 09:02
yes. i check that =/ refers to where the kernel is located base on /boot. thanks for reminding — Pelang, Feb 25 '13 at 09:18

quanta · Accepted Answer · 2013-02-25T08:53:44.807

3

title CentOS (2.6.18-308.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-308.el5 ro root=LABEL=/
crashkernel=128M
        initrd /initrd-2.6.18-308.el5.img

It looks like you put the crashkernel parameter into a new line. This is the reason for Kdump is not operational message. All the kernel parameters must to be put on the same line as kernel:

title CentOS (2.6.18-308.el5)
        root (hd0,0)
        kernel /vmlinuz-2.6.18-308.el5 ro root=LABEL=/ crashkernel=128M
        initrd /initrd-2.6.18-308.el5.img

After reboot, take a look at the /var/log/messages, you'll see something like this:

localhost kdump: kexec: loaded kdump kernel
localhost kdump: started up

and:

# /etc/init.d/kdump start
Starting kdump:                                            [  OK  ]
# /etc/init.d/kdump status
Kdump is operational

kdump: No crashkernel parameter was specified or crashkernel memory reservation failed
kdump: failed to start up

According to this document, try this:

crashkernel=128M@16M

edited Feb 25 '13 at 08:53

answered Feb 25 '13 at 08:08

quanta

50,327
19
152
213

I edited the grub.conf to make the crashkernel in one line. but there is still error in /var/log/messages. I add the errors as additional info on the question above. – Pelang Feb 25 '13 at 08:25
How about this `crashkernel=128M@16M`? – quanta Feb 25 '13 at 08:54
`128@16M` or `128M@16M`? – quanta Feb 25 '13 at 09:00
Show us the new `/var/log/messages` after changing (from this line `Kernel command line...`)? – quanta Feb 25 '13 at 09:05
let us [continue this discussion in chat](http://chat.stackexchange.com/rooms/7663/discussion-between-quanta-and-mark) – quanta Feb 25 '13 at 09:06
Just need to make a reboot to make things work. Running the kdump on the current session without rebooting after the changes will still return the same error. – Pelang Feb 25 '13 at 09:16
That `128M@16M` was the missing piece, putting it in solved the issue and kdump has started. – karatedog May 31 '22 at 13:49

score 1 · Answer 2 · answered May 08 '13 at 19:00

1

Your crashkernel is too small. Try 256M, 384M, or even 512M. The message 'Memory for crashkernel ... is not within permissible range" is telling you that.

answered May 08 '13 at 19:00

Dwight Miller

11
1

based on documentation, 64 should be enough for 12GB RAM. But taking into account other missing information it is probably the documentation that needs tweaking... – karatedog May 31 '22 at 13:50

Cannot start kdump

2 Answers2