history: Large qhst log causes huge delays in updates to UIM

Document ID : KB000009160
Last Modified Date : 14/02/2018
Show Technical Document Details
Issue:

The customer noticed that updates to the QHST file were not visible in UIM for several hours after the entry was logged on the iSeries machine.

Environment:
UIM 8.5robot 5.73 IBMi version: V7R2M0 history 1.05
Cause:

The history probe was going through the whole history file on each interval, which due to the size of the file took very long and caused the latest updates to be posted to UIM as alarm messages with several hours delay.

 

Resolution:

To resolve, the customer had to remove the probe, and ensure that the probe folder was removed (specifically the history.dta) and then deploy the latest probe version, 1.06.  And in addition, they had to make the following changes to the configuration of the probe:

1) Set below keys (present in "setup" section):

MaxNumOfMessages = 100

SetPosToEndOfFile = yes 

2) Create a profile and activate the probe.  

With these changes, the probe will only check for updates of the QHST and not process the whole history on each interval.  

 

 

Additional Information:

A more detailed explanation of the keys mentioned above:

MaxNumOfMessages: Purpose of this key is how many messages are to be displayed on the message section in the probe GUI. By default, its value is -1 (i.e probe display all messages as per previous design of the probe). If the customer environment has lot of old messages then the customer can enable this key, and can set how many messages he wants to display. Less number of message leads to minimum processing. This will also help reducing the CPU Utilization. 


setPosToEndOfFile : By default key value will be set to "no". 
After setting this key's value as "yes", probe will work in update mode. After enabling this key, the probe will jump to the end of the history items and process only updated items. With this, we can avoid processing of lots of old history entries. This will be one time activity i.e on first deployment. After this activity, the key will automatically set to "no".

 

For more details, please also check the probe documentation, found here:

https://docops.ca.com/ca-unified-infrastructure-management-probes/ga/en/alphabetical-probe-articles/history-iseries-qhst-data-monitoring