Troubleshooting
Problem
Your CICS Transaction Server for z/OS (CICS TS) region is spooling SVC dumps to the z/OS SYS1.DUMP datasets with QUIESCE=NO. This allows the system to run dispatchable when the dump is taking place. But, you notice that the MVS system is set non-dispatchable causing severe performance problems.
Cause
SDUMP options are being overridden with QUIESCE=YES by your MVS system default.
The SDUMP that requested the SVC dump was taken with the QUIESCE=NO parameter out of DFHDUSVC. When SDUMPs occur, they should issue the MVS command CHNGDUMP with QUIESCE=NO. The options on the CHNGDUMP are 'or'ed with the equivalent parameters on the SDUMP macro. Therefore, whenever CICS issues SDUMP QUIESCE=NO (allow the system to remain dispatchable), it can be overridden with QUIESCE=YES by your MVS system default.
See System dumps in the CICS TS information center where it states:
The SDUMP macros issued by CICS normally contain the QUIESCE=NO parameter. They might not if the SDUMP is taken because of an abend in CICS SVC code or when altering MRO control blocks. This parameter allows the MVS system to remain dispatchable while the SDUMP is being taken, thus reducing the impact on the system. However if QUIESCE=YES is specified as an MVS system default it will override that specified by CICS. These defaults can be altered by using the MVS CHNGDUMPcommand.
Resolving The Problem
To avoid system impact due to the system being set nondispatchable while the dump is being taken, you can change the SDUMP option QUEISCE from YES to NO using the MVS CHNGDUMP command:
CD SET,SDUMP,Q=NO
Setting Q=NO is done by many customers to avoid system impact and generally does not affect problem determination when using the dump.
Product Synonym
CICS/TS CICS TS CICS Transaction Server
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Document Information
Modified date:
15 June 2018
UID
swg21037865