The Mail Server Framework (MSF) is the distribution framework which supports mail on the IBM i.
To start MSF manually enter the command:
STRMSF NBRMSFJOB(n)
Where n is the number of MSF jobs you want to start. Each MSF job processes a message from start to end before processing the next one in the queue. The more MSF jobs you nominate in the "Number of MSF Jobs" parameter, the more messages can be processed concurrently.
To end MSF manually enter the command:
ENDMSF
The MSF jobs run in subsystem QSYSWRK. Note that by default, QSYSWRK has an autostart job (QZMFECOX) which starts MSF jobs. You may want to customize this autostart job.
For more details about these commands, refer to the chapter Operations Considerations in the AnyMail/400 Mail Server Framework Support Guide (SC41-5411-00).