manual steps to configure fadump

This document (7023180) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 12 Service Pack 3 (SLES 12 SP3)

Situation

After triggering a dump from HMC, the system cycles through all CPUs and then hangs ending in:

----------------------------------[*]---------------------
Oops: System Reset, sig: 6 [#640]
SMP NR_CPUS=2048 NUMA pSeries
....
Instruction dump:
382100c0 e8010010 ebe1fff8 7c0803a6 4e800020 3c4c00e8 3842019c 7c421378
7c000026 90010008 60000000 44000022 <80010008> 7c0ff120 4e800020 7c0802a6
---[ end trace 739e2ca292b87b45 ]--------------------------

In another attempt, after the dumpfile is saved and "makedumpfile Completed." on reboot the system ends up in "Emergency Mode".

Resolution

A future kdump update will include the patch to resolve the problem.
Customers affected by this issue can alternatively contact SUSE Customer Care to request a PTF, temporary fix.

Alternatively the following manual steps to configure fadump can be followed instead:

1. Update bootloader to pass "fadump=on crashkernel=36G" to the kernel:

a. Append "crashkernel=36G fadump=on" to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub file
b. run `grub2-mkconfig -o /boot/grub2/grub.cfg`

2. Rebuild the initrd with dump capturing support. Remember to run these steps everytime there is a change in configuration settings in /etc/sysconfig/kdump file:

a. Set KDUMP_FADUMP to 'yes' in /etc/sysconfig/kdump file
b. run mkinitrd
c. lsinitrd /boot/initrd-`uname -r` | grep kdump

3. Disable kdump service since yast/kdump service updating boot parameters and building initrd seems to have a few problems:

systemctl disable kdump.service

4. Register fadump*

echo 1 > /sys/kernel/fadump_registered

5. Trigger crash.

* Add the fadump registration command in Step4 to a start-up script to ensure fadump is registered on every boot in the absence of kdump service.

Cause

The initrd was not built with dump capturing support.

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.