At 4AM daily, Cisco ISE checks whether there are any logging files that meet the criteria you have set on the Administration > Maintenance > Data Purging page. If so, the files are deleted and recorded in this report. Additionally, Cisco ISE continually maintains a maximum of 80% used storage space for the log files. Every hour, Cisco ISE verifies this percentage and deletes the oldest data until it reaches the 80% threshold again. This information is also recorded in this report.