Troubleshooting the IBM AIX Dynamic System Optimizer

Some problems might require troubleshooting when you are using AIX® Dynamic System Optimizer.

Problem: You migrated to a new system and the ASO daemon was activated, but it is not doing anything.

Reason: The ASO daemon is only supported on systems that are running with POWER7® or newer processors in native mode. If you migrate from a system that is based on POWER7 or a newer processor to a system that is running with a processor that is not supported, the ASO daemon continues to hibernate even if ASO is activated with the asoo command. The ASO log file (/var/log/aso/aso.log) contains a message that indicates the processor version is not supported. When the ASO daemon is in hibernation mode, it is sleeping and does not use any CPU resources. If you migrate back to a system that is running with POWER7 processors in native mode, the ASO daemon is activated automatically.

Resolution: No action is required.

Problem: The ASO daemon process was activated, but it is not doing anything.

Reason: The ASO daemon is started by the srcmstr daemon at boot time. It remains in hibernation mode until the aso_active tunable command is set to 1 by using the asoo command.

Resolution: This situation is normal.

If the ASO daemon needs to be activated, run the following command:

asoo -o aso_active=1

Problem: The ASO daemon process is running in an unsupported environment.

Reason: When ASO determines that the system has an unsupported configuration at startup, the ASO daemon goes into hibernation mode. This automatic hibernation allows the daemon to be activated automatically when the LPAR is migrated to a supported environment.

Resolution: This situation is normal.

If the ASO daemon needs to be activated, run the following command:

asoo -o aso_active=1

Problem: The ASO daemon is not optimizing certain workloads.

Reason: Each optimization has a list of selection criteria that a workload must satisfy to be considered for optimization.

Resolution: See Workload requirements to ensure that the workloads meet the minimum requirements.

Problem: The log file shows lesser utilization than what is shown by other tools.

Reason: The processor utilization that is shown by the log files is only for the workloads that satisfy the eligibility criteria for at least one type of optimization.

Resolution: This situation is normal.

If the ASO daemon needs to be activated, run the following command:

asoo -o aso_active=1

Problem: The memory page size of the workload was promoted by ASO, but it was restored to the original size.

Reason: The kernel reverses actions that are taken by ASO if the changes made by ASO hamper the stability of the system. Using the MPSS optimization as an example, an imbalance of memory pools can cause the kernel to reduce the memory page size of pages that were previously increased by ASO.

Resolution: This situation is normal.

If the ASO daemon needs to be activated, run the following command:

asoo -o aso_active=1

Problem: The ASO daemon is active but are not logging new information in the log files.

Reason: The syslogd daemon is not running. The syslogd daemon must be running to format the messages that are created by the ASO daemon. The resulting log messages are written to the files specified in the /etc/syslogd.conf file.

Resolution: Start the syslogd daemon by entering the following command:

startsrc -s syslogd

Problem: After ASO log files were deleted or moved to a backup location, no information is being logged in the newly created log files

Reason: Any change to the log files or to the /etc/syslog.conf file requires a restart of the syslog daemon.

Resolution: Restart the syslog daemon by entering the following commands:

stopsrc -s syslogd
startsrc -s syslogd