logRotate

Definition

logRotate

The logRotate command is an administrative command that allows you to rotate the MongoDB server log and/or audit log to prevent a single logfile from consuming too much disk space.

You must issue the logRotate command against the admin database in the form:

db.adminCommand({logRotate: <target>})

The logRotate command takes the following parameters:

Parameter	Type	Description
<target>	string	The log or logs to rotate, according to the following: 1 -- Rotates both the server and audit logs server -- Rotates only the server log audit -- Rotates only the audit log
comment	any	optional A message logged by the server to the log file and audit file at time of log rotation.

You may also rotate the logs by sending a SIGUSR1 signal to the mongod process.

For example, if a running mongod instance has a process ID (PID) of 2200, the following command rotates the log file for that instance on Linux:

kill -SIGUSR1 2200

Limitations

• Your mongod instance needs to be running with the --logpath [file] option in order to use logRotate

• Auditing must be enabled in order to rotate the audit log.

Behavior

The systemLog.logRotate setting or --logRotate option specify logRotate's behavior.

When systemLog.logRotate or --logRotate are set to rename, logRotate renames the existing log file by appending the current timestamp to the filename. The appended timestamp has the following form:

<YYYY>-<mm>-<DD>T<HH>-<MM>-<SS>

Then logRotate creates a new log file with the same name as originally specified by the systemLog.path setting to mongod or mongos.

When systemLog.logRotate or --logRotate are set to reopen, logRotate follows the typical Linux/Unix behavior, and simply closes the log file then reopens a log file with the same name. With reopen, mongod expects that another process renames the file prior to the rotation, and that the reopen results in the creation of a new file.

Examples

The following example rotates both the server log and the audit log:

db.adminCommand({logRotate: 1})

The following example rotates only the audit log, and provides a custom message to the log file at time of rotation:

db.adminCommand({logRotate: audit, comment: "Rotating audit log"})