You can set the QlikView Server logging level (verbosity) in the QlikView Management Console.
To configure:
Open the QlikView Management Console
Navigate to System
Open Setup
Select the QlikView Server
Open the Logging tab
Choose your Event Log Verbosity
Choose how frequently you want to Split Files
Press Apply
The settings will take effect immediately, but a service restart is recommended.
Logging level explanations:
Event Log Verbosity = Low License Tracking events, plus events with Severity ID =1, Severity = Error.
Event Log Verbosity = Medium The above, plus events with Severity ID = 2, Severity = Warning.
Event Log Verbosity = High The above, plus events with Severity ID = 4, Severity = Information.
There is also a fourth level, "Debug". That level cannot be activated via the QlikView Management Console, since it should be done only when requested by Qlik Support for advanced troubleshooting. Instructions can be found in How to turn on debug logging for the QlikView Server Service