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 systems using AIX 7.2 and above.
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 7.2 and above.
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 use this link:
This debug tool is available in epkg format following the instructions below:
To download the r2dump debug tool use this link:
https://aix.software.ibm.com/aix/tools/dumptools/
This directory includes the following files:
dbgr2dump.161110.epkg.Z
README.TXT
Install the r2dump debug tool using the emgr command:
# emgr -X -e dbgr2dump.161110.epkg.Z (run from the directory where you saved it)
To verify that the debug tool is applied:
# emgr -l
This directory includes the following files:
dbgr2dump.161110.epkg.Z
README.TXT
Install the r2dump debug tool using the emgr command:
# emgr -X -e dbgr2dump.161110.epkg.Z (run from the directory where you saved it)
To verify that the 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, such as with a normal shutdown, 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.
[{"Type":"MASTER","Line of Business":{"code":"LOB08","label":"Cognitive Systems"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SWG10","label":"AIX"},"ARM Category":[{"code":"a8m0z000000cvz9AAA","label":"Kernel-\u003ERAS issues"}],"ARM Case Number":"","Platform":[{"code":"PF002","label":"AIX"}],"Version":"7.2.0;7.3.0"}]
Was this topic helpful?
Document Information
Modified date:
19 November 2024
UID
isg3T1024564