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We are a team of system programmers and testers that run a Parallel Sysplex on which we perform the final verification of a z/OS release and System z hardware and System Storage before they become generally available to clients. We gather our experiences and recommendations and document them here in our blog.
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In z/OS Version 2 Release 4, SVC dump processing has been enhanced to improve overall dump capture times in an unconstrained environment. When sufficient system resources are available, dump processing will utilize more parallelism to reduce the amount of time it takes to capture the requested dump.
To use this enhancement, PTF UA99457/OA57534 needs to be installed first.To implement this, a new keyword on CHNGDUMP command is introduced.
Therefore, for this system when dumping zFS at that time of day, dynamically enabling OPTIMIZE=YES resulted in an improvement of 4.2 seconds.
2. We dynamically enabled OPTIMIZE=YES for all other systems in the parallel Sysplex.
RO (Z1,Z2,Z3),CD SET,SDUMP,OPTIMIZE=YES
IEE421I RO (LIST),CD SET,SDUMP,O 116
SYSNAME RESPONSES --------------------------
Z1 IEE712I CHNGDUMP PROCESSING COMPLETE
Z2 IEE712I CHNGDUMP PROCESSING COMPLETE
Z3 IEE712I CHNGDUMP PROCESSING COMPLETE
3. Finally we also enabled OPTIMIZE=YES for IPLs of all systems by adding the CD command to our COMMNDxx member. For example, we added the following statement to one of our concatenated parmlib members SYS1.PLEX2.PARMLIB(COMMNDP2):
The times listed in this blog are not meant to be a benchmark or representatives of any clients or workload, they only serve to highlight the relative improvement we saw in our zPET test environment.
If you have any feedback or questions related to what we have done or what you would like to hear more of with regards to our experiences with improving SVC dump capture time, please let us know via comments or email.