@Nickanor  It would be interesting to see a verbose listing of your NiFi  logs directory once it has well exceeded 50 GB archived log files. What you have configured will retain 30 hours of log data.  With each of those 30 hours you may have 1 or more incremental log files (each at 100 MB except for last one each hour). On NiFi restart do you see that the following is cleaning up the archive directory of files older than 30 hours: <cleanHistoryOnStart>true</cleanHistoryOnStart>   I would be inspecting the nifi-app.log to see if you encounter any exceptions around logback or if you see any OutOfMemory (OOM) or no more files (file limits) exceptions that may explain the behavior. Hope this helps, Matt ... View more