Shutting down the CSL

A Common Service Layer (CSL) is comprised of multiple address spaces. As such, you can shut down either an entire CSL or individual CSL manager address spaces.

You can shut down:

  • A single CSL component, such as an instance of ODBM, OM, RM, or SCI
  • A CSL, including all of its components, on a single z/OS® image
  • A CSL, including all of its components, that spans an IMSplex across multiple z/OS images

The entire CSL should be shut down only if no IMSplex components are connected to any CSL managers. You should first issue an IMS /CHE FREEZE or similar command to terminate all the IMSplex components that might be connected to CSL prior to shutting down CSL. If a CQS address space has more than one client, it might not shut down, and you might need to shut it down after all the clients have terminated.

If you shut down an instance of ODBM, OM, or RM and there are other instances of ODBM, OM, or RM active in the IMSplex, IMSplex members can still participate in IMSplex activities; however, an IMSplex member can communicate only with the SCI with which it is registered. If that SCI is shut down, any IMSplex members on the same z/OS image as that SCI cannot communicate with other IMSplex members until that SCI is restarted.

Attention: If you are running Automatic RECON Loss Notification (ARLN), you must keep SCI active (even after IMS is shut down) until all jobs that need access to the RECON data sets have completed.

If you are shutting down only some of the CSL managers to, for example, apply maintenance, you can shut down the individual CSL managers using the STOP command. You do not have to shut down the other IMSplex components if you are only shutting down a CSL manager to apply maintenance.

To shut down the entire CSL on one z/OS image, a program can issue a CSLZSHUT request to SCI that specifies the entire CSL to shut down. Or, you can issue a MODIFY command for one CSL. The MODIFY command shuts down the CSL on the z/OS image that is associated with the SCI that receives the command. The CSL managers quiesce work and then terminate. This command is used to terminate the CSL on a single z/OS image in an orderly manner.

If you shut down the whole IMSplex, a CSLZSHUT request can be issued to SCI that specifies that the entire CSL is to be shut down. Or you can issue the MODIFY command for the entire CSL. The MODIFY command shuts down the CSLs on all z/OS images in a single IMSplex that is associated with the SCI.

Recommendation: Use the CSL SHUTDOWN command with the z/OS MODIFY command interface to shut down the CSL, rather than stopping individual components.

You can shut down the CSL by either: