Look into ALOCxx parmlib option - "SDSN_WAIT  WAITALLOC(YES)"

Regards,

Mark
--
Mark Zelden - Zelden Consulting Services - z/OS, OS/390 and MVS
ITIL v3 Foundation Certified
mailto:[email protected]
Mark's MVS Utilities: http://www.mzelden.com/mvsutil.html




On Thu, 30 Nov 2023 23:17:48 +0000, Schmitt, Michael <[email protected]> 
wrote:

>JOB. If we were starting new we'd use STEP.
>
>-----Original Message-----
>From: IBM Mainframe Discussion List <[email protected]> On Behalf Of 
>Don Leahy
>Sent: Thursday, November 30, 2023 5:12 PM
>To: [email protected]
>Subject: Re: IEF211I - DATA SET RESERVATION UNSUCCESSFUL on relative GDG
>
>[You don't often get email from [email protected]. Learn why this is 
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>
>Are you using GDGBIAS = STEP or GDGBIAS = JOB?
>
>On Thu, Nov 30, 2023 at 13:17 Mike Schwab <[email protected]> wrote:
>
>> Can downgrade from Exclusive (NEW,MOD,OLD) to Shared (SHR) within a job.
>> Cannot upgrade from Shared to Exclusive within a job..
>> Since the first job was SHR, another system / job / task may be browing the
>> data, and prevents a Shared enque being upgraded to Exclusive enque.  This
>> is documented for within a job.
>> I am guessing the Exclusive enque process requires no one be using the DSN
>> at the time of the attempt, but that is not documented on
>> https://www.ibm.com/docs/en/zos/3.1.0?topic=statement-disp-parameter
>>
>>
>> On Thu, Nov 30, 2023 at 9:24 AM Schmitt, Michael <[email protected]>
>> wrote:
>>
>> > We had a production job enqueue failure on z/OS 2.4, that it seemed to me
>> > should have worked. I've been in communication with IBM; they say it is
>> as
>> > expected. But I don't understand why this is normal. Does it make sense
>> to
>> > you? Has it always worked this way?
>> >
>> > Here's the scenario:
>> >
>> > We have a job where the first step has DD DSN=data.set.name(0),DISP=SHR.
>> > The second step has the same data set, but as exclusive: DD DSN=
>> > data.set.name(0),DISP=OLD.
>> >
>> > Someone was browsing the data set when the job started, so they were
>> > holding a shared enqueue.
>> >
>> > The first step ran, and then the second step failed with the IEF211I -
>> > DATA SET RESERVATION UNSUCCESSFUL error.
>> >
>> >
>> > My understanding is that JES acquires the enqueues at the highest level
>> > before starting the job, to prevent deadlocks. IBM says that because it
>> is
>> > a relative GDG, it is unable to acquire the enqueue on the *absolute*
>> > generation before the job started.
>> >
>> >
>> > Contrast it with this case:
>> > 1st step: DD DSN=data.set.name(0),DISP=OLD
>> > 2nd step: DD DSN=data.set.name(0),DISP=SHR
>> > And again, a user is browsing the data set.
>> >
>> > In this case, the job waits until the user's enqueue is released. Which
>> > means that JES tried to get the exclusive enqueue before starting the
>> job,
>> > so waits. Or it means that it stated the job, couldn't get the enqueue,
>> but
>> > waits instead of failing with the IEF211I error.
>> >
>> > So why is the second case different than the first?
>> >
>> >
>> >
>> > ----------------------------------------------------------------------
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>> >
>>
>>
>> --
>> Mike A Schwab, Springfield IL USA
>> Where do Forest Rangers go to get away from it all?
>>
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