> I have there more than a half year old builds. When I set 30 days then > I would like to ask you if the older builds are deleted when jenkins > is starting or when the same job is building?
the builds are deleted after next build is run and finished. If you want to delete them without running new builds, go to script page ($JENKINS_URL/script) and run jenkins.model.Jenkins.instance.items.each { it.logRotate() }