What are the files in the On-Demand-Log directory in a Data Collector?

Document ID : KB000011871
Last Modified Date : 14/02/2018
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Introduction:

This article discusses and explains the existence of log files created in a Data Collector. These are logs related to debug data and are infrequently reviewed for data.

Question:

What is the reason for the existence of this directory and its contents on the Data Collector host?

$DC_HOME/IMDataCollector/apache-karaf*/dcdebug/On-Demand-Log

When installed in the default /opt location the path is:

/opt/IMDataCollector/apache-karaf*/dcdebug/On-Demand-Log

Environment:
CA Performance Manager Data Collector releases r2.6 or newer
Answer:

In releases before the r2.6 version all Discovery messaging was stored in memory on the Data Collector. If it was restarted this data was lost.

Starting with the r2.6 release this discovery messaging began to be stored in files in order to retain its history through Data Collector service restarts.

Some details about the files found within this location:

  • Each file represents data from a single device
  • Each file is named with the IP address of the device the data represents
  • Each file should be no larger than 1 MB
  • Each file contains Discover messaging only
  • Files are in binary form and are read by the searchdebug.jsp when called via the <DA_HOST>:8581/dcdebug/searchdebug.jsp URL
  • No log rotation configuration is available to manage these files
  • All other dcdebug page related data is stored in memory only on the running Data Collector server
  • These logs are the only debug data available via the dcdebug page that is persistent through DC restarts

These files can be deleted. They can be deleted without requiring any kind of Data Collector service stop/start cycle.

These files should only ever be deleted if an administrator of a CA Performance Manager installation is aware of the impact of that action. Doing so will result in the loss of discovery related messages for a device. If this loss is acceptable the file can be safely deleted to free up space.

Once more we should be aware that deleting these files causes the loss of historical discovery messaging for a device. This is data which is often necessary for the debug and troubleshooting of discovery related problems.

Additional Information:

Upgrading an already installed DC but the reported disk size requirements per the installation seem excessive, or higher than expected? Please see Knowledge Base Article ID TEC1127457 if disk consumption issues related to these logs is a concern.