Clear iRule info in the ltm log file

You could use sed for this task. For example, in my /var/log/ltm file I see entries like:

Apr 24 12:31:01 nielsvs-bigip.vosko.lab info sdmd[6492]: 018e0017:6: pid[11267]  plugin[/Common/office365_endpoints_plugin.office365_endpoints_extension] info: latest version available is: 2019032800
Apr 24 12:31:01 nielsvs-bigip.vosko.lab info sdmd[6492]: 018e0017:6: pid[11266]  plugin[/Common/office365_endpoints_plugin.office365_endpoints_extension] info: latest version available is: 2019032800

These entries can be removed by using sed:

sed -i '/office365_endpoints_plugin.office365_endpoints_extension/d' /var/log/ltm

After this you'll need to restart syslog-ng.

bigstart restart syslog-ng

Make sure that you use an expression that only matches the lines you want to remove.