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IBM i 7.2 Improved Temporary Storage Tracking

April 14, 2015

This is another article in the series of blogs reviewing the enhancements in IBM i 7.2 for improved tracking of temporary storage. Part 4 has the links to the prior blogs on this topic.
 
This blog will review the notification support that was added to the 7.2 release to allow you to set limits (thresholds) and have messages sent when temporary storage limits are being hit.
 
Three enhancements provide the capability for notification when there may be a temporary storage issue to investigate. They are:
 
1.       System monitor metric for temporary storage utilization
2.       CPF1164 message
3.       The control temporary storage API
 
Let me summarize each one.
 
First, with the 7.2 System Monitors, you can create a monitor on the temporary storage utilization for the entire system. This is a simple approach.
 
In addition, with 7.2 system monitors, the disk storage utilization monitor metrics that were available on prior releases were expanded to include not just the overall system view, but to separate the information by system ASP, user AP or independent ASP, as the following screen capture shows:

iCan-April-14.jpg
 
Second, the CPF1164 message was enhanced to include the amount of temporary storage used by the job that ended. This additional information was added to the Cause section in the message. If you use the CPF1164 message for analysis of job information, you now have this additional metric available.
 
Finally, there is the new API, Control Temporary Storage (QWCCTLTS), which allows you to set a soft limit on the amount of temporary storage used. When a systemwide limit is set, CPF090A will be sent to the QSYSOPR message queue when system limit is reached.
 
For example, if you wanted to use this API to set a systemwide limit for notification when 80% of the storage in the system ASP is used, you would invoke the API like this:
 
                 CALL QWCCTLTS PARM(*SETLMTPCT *ALL 80)
If/when the system ASP temporary storage usage gets to 80%, CPF090A will be sent.
If you have set a systemwide threshold using this API, extended system status (WRKSYSSTS then F19) will display additional information. The screen capture below shows the two new extended system status fields.
 
iCan-April-14-2.jpg
 
You can also se this API to set a limit for a category. CPI11AB will be sent to the QSYSOPR message queue when the limit for that category is reached. Setting limits on categories requires some detailed knowledge of how the 7.2 temporary storage accounting works, so you probably would only use this option when recommended by IBM Service.

When this API is used to set notification limits, the messages will be sent hourly when the limit is exceeded. Increasing the bucket size limit resets the threshold trigger for the system bucket.
 
While 7.2 has these enhancements for notification of temporary storage limits, you should not forget about the storage system values. The storage lower limit (QSTGLOWLMT) and storage lower limit action (QSTGLOWACN) system values continue to be useful controls for overall system consumption of storage.
 

Posted April 14, 2015| Permalink

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