R2dump debug tool

R2dump debug tool

Troubleshooting


Problem

Customers may face a situation where a server is rebooted with no dump and nothing to explain the reason for the reboot in the error report or in the console log. Most commonly this is seen with customer using an Oracle clustering product, such as RAC or Grid, or with Veritas VCS. Customers are usually referred to these vendors to examine application logs for root cause. A product vendor may ask IBM to provide more information about the system state when the reboot command was issued. AIX development support has created a kernel extension, called r2dump. The r2dump tool loads a kernel extension that replaces the reboot system call in the AIX kernel, with code that will simply force system dump instead of reboot. It can be used on AIX 6.1 TL06 or ( later versions) and on any AIX 7.1 and 7.2 systems.

Symptom

A reboot with no dump to analyze the root cause.

Cause

In most cases, customer using an Oracle clustering product, such as RAC or Grid, or with Veritas VCS may experience a reboot with no dump.

Environment

AIX 6.1 TL06 up to 7.2

Resolving The Problem

The r2dump debug tool loads a kernel extension that replaces the reboot system call in the AIX kernel, with code that will simply force system dump instead of reboot.

This debug tool is available in epkg format following the instructions below:

To download the r2dump debug tool:

ftp://ftp.software.ibm.com/aix/tools/dumptools/

This include:

dbgr2dump.161110.epkg.Z
README.TXT

To apply the r2dump debug tool:

# emgr -X -e dbgr2dump.161110.epkg.Z (run from the directory where you saved it)


To see if debug tool is applied:

# emgr -l
To remove:
#emgr -r -L dbgr2dump
----------------------------

To enable the tool, run "/opt/AIX/r2dump/r2dump -e /opt/AIX/r2dump"

To automatically reload the extension after a system reboot, put this command in inittab:
r2dump:2:once:/opt/AIX/r2dump/r2dump -e /opt/AIX/r2dump>/dev/console 2>&1

If you want to reboot the system without collecting a dump, you can simply unload the kernel extension:

/opt/AIX/r2dump/r2dump -d /opt/AIX/r2dump


Or, you can add the above line to /etc/rc.shutdown and the kernel extension will be automatically disabled when you run a reboot or shutdown from the command line.

Conclusion

This is a useful tool to find out what is causing unexplained system reboots.

0 (0)
Article Rating (No Votes)
Rate this article
Attachments
There are no attachments for this article.
Comments
There are no comments for this article. Be the first to post a comment.
Full Name
Email Address
Security Code Security Code
Related Articles RSS Feed
Managing System Dump Devices sysdumpdev
Viewed 3795 times since Mon, Jul 9, 2018
AIX Health Check basic
Viewed 4925 times since Fri, Jun 8, 2018
AIX hangs on boot? How to debug boot process on AIX systems
Viewed 11767 times since Thu, Feb 21, 2019
AIX perf how to
Viewed 19293 times since Tue, Aug 14, 2018
n a perfect world....rootvg would always reside on hdisk0
Viewed 2464 times since Thu, Jun 6, 2019
AIX, Red Hat, Security, System Admin↑ System-wide separated shell history files for each user and session
Viewed 2424 times since Fri, Apr 19, 2019
Kerberos authentication configuration for AIX servers
Viewed 11257 times since Mon, Jun 25, 2018
AIX www web Links
Viewed 3528 times since Fri, Apr 19, 2019
SSH-COPY-ID on AIX. SSH remote AIX’s box without password
Viewed 17633 times since Thu, Feb 21, 2019
How to start daemons at the system startup in AIX servers
Viewed 2643 times since Tue, Jun 18, 2019