MongoDB Documentation, Release 3.0.4 Default Log Rotation Behavior By default, MongoDB uses the --logRotate rename behavior. With rename , mongod or mongos renames the current log file by appending a UTC timestamp to the filename, opens a new log file, closes the old log file, and sends all new log entries to the new log file. mongod -v --logpath /var/log/mongodb/server1.log You can also explicitly specify logRotate --rename . Step 2: List the log files In a separate terminal, list the matching files: ls /var/log/mongodb/server1.log * The results should include one log file, server1.log . Step 3: Rotate the log file. Rotate the log file by issuing the logRotate command from the admin database in a mongo shell: use admin db.runCommand( { logRotate : 1 } ) Step 4: View the new log files List the new log files to view the newly-created log: ls /var/log/mongodb/server1.log * There should be two log files listed: server1.log , which is the log file that mongod or mongos made when it reopened the log file, and server1.log.<timestamp> , the renamed original log file. Rotating log files does not modify the “old” rotated log files. When you rotate a log, you rename the server1.log file to include the timestamp, and a new, empty server1.log file receives all new log input. New in version 3.0.0. Log rotation with --logRotate reopen closes and opens the log file following the typical Linux/Unix log rotate behavior. mongod -v --logpath /var/log/mongodb/server1.log --logRotate reopen --logappend You must use the --logappend option with --logRotate reopen . Step 2: List the log files In a separate terminal, list the matching files: The results should include one log file, server1.log . ls /var/log/mongodb/server1.log * Step 1: Start a mongod instance, specifying the reopen --logRotate behavior. Log Rotation with --logRotate reopen Chapter 5. Administration 232 Step 1: Start a mongod instance.