Do not remove the log files manually when a WebSphere MQ queue manager is running. If a user inadvertently deletes the log files that a queue manager needs to restart, WebSphere MQ does not issue any errors and continues to process data including persistent messages. The queue manager shuts down normally, but fails to restart. Media recovery of messages then becomes impossible.
Users with the authority to remove logs that are being used by an active queue manager also have authority to delete other important queue manager resources (such as queue files, the object catalog, and WebSphere MQ executables). They can therefore damage, perhaps through inexperience, a running or dormant queue manager in a way against which WebSphere MQ cannot protect itself.
Exercise caution when conferring super user or mqm authority.