The logging options have been changed starting with Equitrac Office / Express 5.6. This article describes the different options and when they should be used.
There are two predefined settings (Standard and Diagnostic) and the Custom setting, where logging can be specified more precisely.
Journaling should be enabled only when investigating an issue with the system, as it can create a lot of data in the logs.
Immediate flush slows down logging, but ensures that log data is written to disk immediately. This should also be set only during investigations.
The severity filter specifies the amount of logging. DEBUG logs everything and OFF logs nothing. This setting does not affect journaling.
It is recommended to use the predefined Standard setting for production environments. It turns off all the slow things, but will still log warnings and errors. However, a custom setting with both journaling and immediate flush disabled and the severity filter set to OFF would provide the least impact.
The predefined Diagnostic setting should be used when providing logs to development for investigation, as it enables all options.