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Z NET,QUICK fails to terminate VTAM when SNAMGMT=YES

Technote (troubleshooting)


Z NET,QUICK hangs before VTAM termination can complete. The VTAM start option SNAMGMT=YES was set at the time the Z NET,QUICK command was entered. The VTAM termination hang is indicated by the fact that the following expected termination messages were not issued:


Diagnosing the problem

This VTAM termination hang problem will occur only if the VTAM start option SNAMGMT is set to YES at the time VTAM termination is attempted. When VTAM is terminated, socket connections for VTAM will exist only in that case.

When SNAMGMT is set to YES, VTAM termination attempts to close all socket connections.

If OMVS is available when VTAM is terminated, VTAM will request OMVS to close down VTAM's socket connections. When OMVS has completed that request, OMVS will notify VTAM. VTAM will then issue message IST1930I SOCKET CLOSED BY SNAMGMT SERVER SUBTASK, and VTAM termination will proceed to successful completion.

However, if OMVS is not available when VTAM is terminated, the request from VTAM to OMVS to shut down its socket connections will never be completed, and VTAM termination will hang with VTAM waiting on OMVS to close down the connections.

You might have shut down OMVS by using the F OMVS,SHUTDOWN command before terminating VTAM.

Resolving the problem

You can take the following two alternative solutions to prevent this VTAM termination hang problem:

  • Terminate VTAM before shutting down OMVS. This modification to your VTAM and OMVS shutdown procedure will allow the VTAM termination to run to successful completion. VTAM will issue message IST1930I to indicate that all socket connections have been successfully closed, and message IST102I will be issued to indicate that VTAM termination successfully completed.
  • Issue command F NET,VTAMOPTS,SNAMGMT=NO before shutting down OMVS. This command will ensure that message IST1930I is issued, indicating that all socket connections have been successfully closed. When IST1930I is issued, you can shut down OMVS. Later, when VTAM is terminated, termination will run to successful completion. This approach is appropriate if you want to shut down OMVS but do not want to shut down VTAM just yet.

Document information

More support for: z/OS Communications Server

Software version: 1.11, 1.12, 1.13, 2.1

Operating system(s): z/OS

Reference #: 1596609

Modified date: 2013-04-24