How to increase jenkins logger size? I use Jenkins log recorders as described in docs:
https://www.jenkins.io/doc/book/system-administration/viewing-logs/
It works, but log is only about 255 lines long, which is too short for my processing.
Newest lines are shown, I cant reach older logs, so I dont know what happened in the beginning.
How do I increase this size? I would like to keep at least 1MB of data.
I'm pretty sure this Jenkins system property will do the trick:

hudson.util.RingBufferLogHandler.defaultSize

tuning
Since: 1.563
Default:  256
Description: Number of log entries in loggers available on the UI at /log/

You can also custom Configure Loggers for Jenkins or create a logger in Jenkins for troubleshooting and diagnostic information that capture specifics you are looking for.
Additional references:
JENKINS - Logging
JENKINS - Logger Configuration
Or, if you are the admin, you should be able simply to scan the logs on the filesystem. Review what log rotation options and retention you may have.