5 Replies Latest reply: Jul 11, 2012 9:43 AM by Dude! RSS

    kdump: No crashkernel parameter specified for running kernel

    908245
      Hi all,


      Does someone know how to solve this problem: kdump: No crashkernel parameter specified for running kernel

      kdump refuses to start during system start

      I did a fresh installation of Oracle Linux 6.3, but OL6.3 seems to be buggy from the very beginning.



      Thanks a lot.
        • 1. Re: kdump: No crashkernel parameter specified for running kernel
          Tommyreynolds-Oracle
          You had a chance to configure kdump during the initial install.

          To do it now, be sure that you have a clause similar to:
          crashkernel=128M@0
          on your kernel command line in the */etc/grub.conf* setup.

          Then make sure you have the kdump service going and reboot:
          # /sbin/chkconfig kdump on
          # /sbin/service kdump start
          # /usr/bin/reboot
          For any problems look in the */var/log/dmesg* and */var/log/messages* files.

          HTH
          • 2. Re: kdump: No crashkernel parameter specified for running kernel
            Dude!
            Did you enable "kdump" during the installation? By default it is disabled.

            Unless you know what kdumps are used for chances are most likely that you really don't need it.

            Your problem seems to be described in the OS release notes:
            https://oss.oracle.com/ol6/docs/RELEASE-NOTES-U3-en.html

            +6. kdump service fails to start with Unbreakable Enterprise Kernel+

            When configuring the crash kernel for the UEK, only standard crash kernel settings, e.g. crashkernel=128M@32M, are supported. The new setting used by the RHCK, i.e. crashkernel=auto, is not supported and will cause the kdump service to fail to start.

            What is the content of /etc/grub.conf file?

            Here is an older similar thread that might be useful:
            Kdump Not Starting On 2.6.32-200.13.1.el5uek No crashkernel parameter spec
            • 3. Re: kdump: No crashkernel parameter specified for running kernel
              Tommyreynolds-Oracle
              Unless you know what kdumps are used for chances are most likely that you really don't need it.
              Sorry to disagree, but a VMCORE, produced by a kdump, is ultimately useful to technical support should an incident occur. Yes, it's beyond the ken of administrators, but they are not the intended audience.
              • 4. Re: kdump: No crashkernel parameter specified for running kernel
                908245
                Your solution works great. I hope that oracle will fix that issue and it will be not necessary to fix it manually.

                I've just added crashkernel=128M@0 to the default kernel in /boot/grub.conf

                Many thanks to
                TommyReynolds.
                • 5. Re: kdump: No crashkernel parameter specified for running kernel
                  Dude!
                  I did not mean to discredit the purpose of the crash dump, but the system administrator needs to be aware of the possible consequences should a kernel crash really occur. Sure, the memory image of a crashed kernel can be useful if you have the knowledge or paid technical support. Technical support may even instruct the user to enable kdump to analyze a kernel problem.

                  However, I think the reason why kdump is disabled by default is a valid safe-guard to protect the system from running out of disk space after a few crashes. Most people will simply restart the system if it crashes, and some systems automatically reset if the system timer stops. I would not recommend to enable Kdump unless the system is a production system and covered by a paid technical support contract.