I'll be upfront and say first that you are entering unsupported territory, and you are at risk of losing log messages if you switch to using an external rotation strategy. There's no guarantee that when the log file is externally manipulated Log4j transitions seamlessly and you don't lose log messages or have log messages partially written across two files. It doesn't matter if you use a rename/new strategy, or something like
If you insist on doing this, you need to change the appender in the default
log4j2.properties configuration from the rolling file appender to a different appender like the file appender, and remove the size-based triggering policy. You'll need to consult the Log4j docs for the specific parameters for your use case.