Kernel crash dump (vmcore) not getting generated inside partition mounted under /var/crash.

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux Server (RHEL) 5.
  • Red Hat Enterprise Linux Server (RHEL) 6.
  • Red Hat Enterprise Linux Server (RHEL) 7.

Issue

  • vmcore not getting generated inside the partition mounted under /var/crash.

Resolution

  • This happens if /var/crash mount point was defined after the generation of the kdump initrd image. Hence in order to update the kdump initrd image with changes in /var/crash path you need to regenerate the initrd image after mounting the /var/crash partition..

Kindly run below two commands in sequence to regenerate the initrd image for kdump. Once done test the kdump and check if vmcore is getting generated under /var/crash.

# touch /etc/kdump.conf
# service kdump restart

Root Cause

  • The /var/crash mount point was defined after the generation of the kdump initrd image. Thus the kdump initrd image is not updated with changes in /var/crash path.

Diagnostic Steps

  • The kdump is configured to generate vmcore in /var/crash as per /etc/kdump.conf given below:

    path /var/crash
core_collector makedumpfile -c --message-level 1 -d 31

  • Contents of /etc/fstab:

    /dev/mapper/VolGroup00-lv_root    /    ext4    defaults    1    1
/dev/mapper/VolGroup00-crash    /var/crash    ext4    defaults    1    2

    But vmcore is getting generated in side /dev/mapper/VolGroup00-lv_root which is the default path for /var/crash before /var/crash mount point was defined.

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