Way back in V5R1, IBM introduced the ability to route FTP and SMTP workloads to their own subsystems. By default, FTP and SMTP server jobs run in the QSYSWRK subsystem, along with a lot of other IBM i server jobs. The Server Table in the IBM i Knowledge Center documents all the IBM i server jobs along with the default subsystem in which they run. The server table does state the subsystem is configurable for these servers, but it doesn’t give you any more information.
If you are doing a lot of file transfers or SMTP email on your IBM i partition, you may want to take advantage of subsystem configuration to isolate those workloads from other work in the QSYSWRK subsystem.
This is very simple to do—you just need to specify the subsystem description for where you want the jobs to run on the Change FTP Attributes (CHGFTPA) or Change SMTP Attributes (CHGSMPTA) command. You specify the subsystem name and library name (the library must already exist) on the appropriate command, and the system will automatically create the subsystem for you if it does not yet exist. It will also create the job queue if needed. Note that if you allow the system to automatically create the subsystem description, it will use the *BASE pool; you may want to create the subsystem description yourself to fully take advantage of work management features.
You can also do the configuration on the graphical interface with Navigator for i. TCP/IP Server jobs are found under the Network tasks:
Simply select the Properties for FTP or SMTP servers.
You will find the subsystem configuration option for FTP servers on the General panel.
When you start the FTP server, it will automatically start the configured subsystem if it is not already started.
For SMTP, it is on the Additional Parameters panel.
You will need to end and then start the SMTP server for the jobs to run the configured subsystem. When SMTP starts, it will also start the configured subsystem if it is not already running.
Once you have this set up, the jobs will run in the configured subsystem. The screen capture below shows the FTP jobs running in my subsystem:
This blog post was edited for currency on November 6, 2020.
This blog post was originally published on IBMSystemsMag.com and is reproduced here by permission of IBM Systems Media.