Parameter and Command Reference > Logging Configuration Parameters > LogOldAction 

LogOldAction 
Determines how log files are handled when the maximum number of log files is exceeded. Type one of the following to determine how log files are handled when the LogDirectory has reached the maximum number of log files, as determined by the LogMaxOldFiles parameter:
 
 
Logging and/or LogStream
If you set this parameter in the Logging and LogStream sections, the setting in the LogStream section takes precedence for the specified log stream.