Increasing the size of a subsystem-to-monitor file (for non-Sysplex environments)

Select this step to increase the size of a communication file in a non-Sysplex environment where the MVS System Logger will not be used.

Control‑O and CMEM transfers FORCEJOB and RESOURCE requests to Control‑M through the subsystem-to-monitor communication file.

When Control‑M is active, it processes all written requests. When the Control‑M monitor is shut, Control‑O and CMEM continue processing events and write the required actions to the communication file. All the actions processed by Control‑O and CMEM when the Control‑M monitor is shut down will be performed by the monitor when it becomes active again.

The subsystem-to-monitor communication file is a "wraparound" file. Control‑M is usually active most of the time, and processes Control‑O and CMEM requests a few seconds after they are written. Therefore, the size of the subsystem-to-monitor communication file need not be too large.

However, if the Control‑M monitor is down for a long time while Control‑O and CMEM are active, and the subsystem-to-monitor communication file is not large enough, old and unprocessed records may be overwritten by new records. When unprocessed records are overwritten by new requests, message CTM448E indicates that data was overwritten. This message also indicates how many communication file records were lost and on which computer.

Follow the steps below to increase the size of the subsystem-to-monitor communication file:

1. Stop the Control‑M monitor.
2. If Control‑O is installed and active, stop the Control‑O monitor using one of the following operator commands:

   F CONTROLO,STOP

   P CONTROLO

   This command should be issued in all the computers where Control‑O is active.

3. If CMEM is active, stop it using one of the following operator commands:

   F CTMCMEM,STOP

   P CTMCMEM

   This command should be issued in all the computers where CMEM is active.

4. Perform Step 6.3 – Specify IOA computers (optional) to update the SYSID parameter in the IOACPRM member to match the new configuration. Delete the CTM2SBS file and all the subsystem-to-monitor files.
5. Reformat all the communication files - the CTM2SBS file and all the subsystem-to-monitor files defined in the SYSID parameter in the IOACPRM member. For details, see Step 7 – Install Event Manager (CMEM)/Control-O interface.
6. Start the Control‑M monitor.
7. If Control‑O is installed, start the Control‑O monitor in all computers where Control‑O should be active.
8. If the CMEM subsystem was active in one or more computers, start it using the following operator command:

   S CTMCMEM

   This command should be issued in all computers where the CMEM subsystem should be active.