On Tue, 10 Feb 2009 17:05:49 -0500, David Andrews <d...@lists.duda.com> wrote:
>On Tue, 2009-02-10 at 16:29 -0500, Dave Salt wrote:
>> It's very important that the jobs execute in the same sequence in
>> which they were submitted.
>
>Briefly ignoring Mark's plea to consult the archives (sorry Mark), you
>might consider reducing the number of JES2 converter subtasks to 1. If
>you have multiple converters, then jobs can enter the job queue in
>something other than submission sequence.
>
Now you've done it... you re-hashed! :-) And so now I feel compelled
to post the same warning I did last may in case Dave doesn't check
the archives:
"With CNVTNUM=1, the system can "hang" depending on the characteristics
of the job stream. See z/OS JES2 Initialization and Tuning Guide for
more information on job queuing and how to control job execution
sequence."
>From init & tuning:
"JES2 is limited to processing your workload in a serial manner without
respect to the types of jobs that are being submitted. Large batch jobs
and TSO logons are treated in a similar way.
Each of the job's resources are required when the job executes. As such,
any migrated libraries and data sets that the job needs, must be
restored before the job can execute. The time spent waiting for these
migrated resources can backup other jobs in the queues.
System hangs and deadlocks can occur in the system. When jobs are
waiting for resources that have been migrated, the migration program
needs to run and restore these resources. The migration program is often
a job that needs JES2 conversion before it running. Since only "1" JES2
converter processor is defined to do the conversion and it is waiting,
the migration cannot occur and the system becomes deadlocked. As an
example, this condition can occur for jobs that need JCLLIB data sets,
which have been migrated by a product like DFHSM.
If a job has an exclusive ENQ on a JCLLIB data set and another job needs
that JCLLIB data set, the job must wait till the ENQ is released."
Mark
--
Mark Zelden
Sr. Software and Systems Architect - z/OS Team Lead
Zurich North America / Farmers Insurance Group - ZFUS G-ITO
mailto:mark.zel...@zurichna.com
z/OS Systems Programming expert at http://expertanswercenter.techtarget.com/
Mark's MVS Utilities: http://home.flash.net/~mzelden/mvsutil.html
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