Thanks for the response.
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf
Of McKown, John
Sent: Wednesday, October 10, 2012 1:58 PM
To: [email protected]
Subject: Re: Question about Catalogs and VSAM
Bottom line: You are correct. GRS will normally propagate the data set ENQ
around the entire SYSPLEX. So only one system can have exclusive control at a
time. z/OS does not include the data set's volume name in the ENQ, so z/OS
"believes" that there is only one such data set. There is not a general way
around this, other than to set up GRS to convert the SYSTEMS level ENQ to a
SYSTEM level ENQ. Which, IMO, is a very dangerous and unwise thing to do.
The philosophy behind using a SYSPLEX is to present the user with a set of z/OS
images (LPARs) that appears to be a single image. So having z/OS image-specific
data sets with identical names is basically "not nice". I don't know why anyone
would want to do this. Now, I have done some really "weird" (at least to me)
things when I needed to have separate data sets on the different images but
wanted a single data set name to be used. This is possible using an ALIAS with
the SYMBOLICRELATE parameter. Suppose you have 4 images named: SY1, SY2, SY3,
and SY4. When running on SY1, you want to use the physical DSN of HLQ.SY1.JUNK;
on SY2, you want to use HLQ.SY2.JUNK, and so on; replacing the second qualifier
with the name of the image. But you don't want to "hard code" the image name in
the DSN in your JCL (or TSO ALLOCATE command or ???). You can do this my making
HLQ.JUNK point to a system specific name using a DEFINE ALIAS command in IDCAMS
similar to:
//IDCAMS EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=*
//SYSIN DD *
DEF ALIAS(NAME('HLQ.JUNK') -
SYMBOLICRELATE('HLQ.&SYSNAME..JUNK'))
/*
Of course, the HLQ high level should point to a shared catalog, not different
catalogs as in your case.
Hope this may be of some use to you.
--
John McKown
Systems Engineer IV
IT
Administrative Services Group
HealthMarkets(r)
9151 Boulevard 26 * N. Richland Hills * TX 76010
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> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:[email protected]]
> On Behalf Of Daniel Allen
> Sent: Wednesday, October 10, 2012 3:44 PM
> To: [email protected]
> Subject: Question about Catalogs and VSAM
>
> We have a SYSPLEX of four LPARs, each LPAR has a separate Master
> Catalog and a separate User Catalog defined to the Master Catalog.
>
> Each Master Catalog has an alias called JUNK, which is defined to a
> User Catalog.
>
> If I define a dataset on all four LPARs called JUNK.DATASET, I have
> four separate files, each residing in their own SMS Storage Group.
>
> If I open the JUNK.DATASET with exclusive control on the first LPAR, I
> would think that I cannot open the JUNK.DATASET with exclusive control
> on the other LPARs.
>
> Is this correct ? If so, is there a way to get around it ?
>
> I am thinking this is a GRS issue but I do not have any proof.
>
>
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