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Rotate Agent Log Files


During normal operation, the Monitoring Agent and Backup Agent report a live account of all activity and operations to a log file. When a log file reaches a user-specified limit, the system must replace or rotate the log file.

On Linux systems, the logrotate command automatically copies, renames, compresses, and removes older archived log files.

For programs that do not have an interface to close the log file, use copytruncate command to rotate log files without stopping the process. For Ops Manager, this allows you to rotate log files without restarting the backup and Monitoring Agents.

Log Rotation With logrotate

logrotate is available on most Linux systems. Check the logrotate.conf configuration file exists in the /etc folder or install the logrotate package.

Configure the behavior of the logrotate command in the logrotate.conf configuration file. Open this file then add entries and directives for the monitoring and Backup Agent log files.

The logrotate.conf file includes a set of directives in a structured format, for example:

#sample configuration file

<backup agent log file path> {
    size 10M

<monitoring agent log file path> {

In this example, the entries and directives in the logrotate.conf configuration file will rotate the Backup Agent log file once it exceeds 10MB in size and compress the old file using gzip (default). logrotate rotates the log files for the Monitoring Agent daily and compresses previous log files with gzip. The copytruncate directive ensures permits log rotation without restarting the agent process.

Common logrotate Configuration Directives

See the Additional Information section below for links to complete documentation of logrotate.


Sets a global option to compress log files after rotating each file. Place compress within directive blocks if only some log files require compression.

<backup agent log file path> or <monitoring agent log file path>

Sets commands specific to the Backup Agent or Monitoring Agent log file. You set the name and location of the agent log files when you installed the agents. The default log file path with agents installed from the .rpm and .deb packages is /var/log/mongodb-mms/monitoring-agent.log or /var/log/mongodb-mms/backup-agent.log. For agents installed from .tar.gz archives the default log files are at /log/mms-agent/monitoring-agent.log and /log/mms-agent/backup-agent.log.


Rotates the log file once it exceeds 10 megabytes in size. The file size is configurable.


Rotates the log file without shutting down the agent software. This directive copies the contents of the current log file to a new archive file then deletes the contents of the current log file. The process adds new log messages to the, now empty, log file. Use this directive to rotate logs file without restarting the Backup and Monitoring Agents.

When using copytruncate the create option has no effect because the old log file stays in place. There also is a small time window between copying the log file and emptying it. In this mode, logrotate may lose some logging information.

daily, weekly, monthly

If you must rotate logs every day, week, or month, then use the daily, weekly, monthly directives and remove the size directive. size is not compatible with frequency-based log rotation.

Global and Local Scope for Configuration Directives

Configuration directives have either a global scope or local scope.

In the example above, compress is a global configuration directive and size and copytruncate local directives. Place global directives at the top of the logrotate.conf file and apply to all log files defined within the file. Local directives appear only in a specific log file definition in the logrotate.conf file. Local configuration directives have no effect on other log files.

Additional Information

See also the logrotate Man Page.