Verifying kdump configuration by simulating a panic event on Redhat 5 virtual machines

Products

• VMware vSphere ESXi

Issue/Introduction

kdump writes a dump of the boot kernel's address space to a file when a kernel panic or other fatal error occurs.

This article provides instructions for simulating a panic event on a Redhat 5 virtual machine.

Symptoms:

Cause

Resolution

Simulating a panic allows you to verify that kdump is configured properly:

Note: Prior to simulating the panic, ensure that there is enough free disk space in the filesystem of the virtual machine to write the crash dump. This file is approximately the size of the memory being used by the virtual machine at the time of the panic.

1. Run this command to make sure the kdump service is working:
   
   # service kdump status
   
   
2. If not, run these commands to turn it on and run it:
   
   
   # chkconfig kdump on
   # service kdump start
   
   
3. Run these commands to force the crash and dump:
   
   
   # echo 1 > /proc/sys/kernel/sysrq
   # echo c > /proc/sysrq-trigger

This causes the kernel to panic. The system next boots into the kdump kernel. After the dump is finished and your system is brought back up with the boot kernel, check the log file at the location you specified.

Additional Information

For more information about proper kdump configuration, see:

• RHEL 6: http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/ch-kdump.html
• RHEL 5: http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Deployment_Guide/ch-kdump.html
• Using kdump and kexec with the MRG Realtime Kernel: http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_MRG/1.3/html/Realtime_Tuning_Guide/sect-Realtime_Tuning_Guide-Realtime_Specific_Tuning-Using_kdump_and_kexec_with_the_RT_kernel.html

Note: The preceding links were correct as of September 23, 2015. If you find the link is broken, provide feedback and a VMware employee will update the link.

Note: When running via an RDP session, the RDP session must be configured to allow forwarding of the SysRq key used by RedHat Linux. When starting the session with mstsc.exe, navigate to the Local Resources tab and set Apply Windows key combinations to "On the remote computer".